Sample records for solid phase direct

  1. Solid phase DNA extraction on PDMS and direct amplification.

    Pasquardini, Laura; Potrich, Cristina; Quaglio, Marzia; Lamberti, Andrea; Guastella, Salvatore; Lunelli, Lorenzo; Cocuzza, Matteo; Vanzetti, Lia; Pirri, Candido Fabrizio; Pederzolli, Cecilia


    In this paper we report an innovative use of Poly(DiMethyl)Siloxane (PDMS) to design a microfluidic device that combines, for the first time, in one single reaction chamber, DNA purification from a complex biological sample (blood) without elution and PCR without surface passivation agents. This result is achieved by exploiting the spontaneous chemical structure and nanomorphology of the material after casting. The observed surface organization leads to spontaneous DNA adsorption. This property allows on-chip complete protocols of purification of complex biological samples to be performed directly, starting from cells lysis. Amplification by PCR is performed directly on the adsorbed DNA, avoiding the elution process that is normally required by DNA purification protocols. The use of one single microfluidic volume for both DNA purification and amplification dramatically simplifies the structure of microfluidic devices for DNA preparation. X-Ray Photoelectron Spectroscopy (XPS) was used to analyze the surface chemical composition. Atomic Force Microscopy (AFM) and Field Emission Scanning Electron Microscopy (FESEM) were employed to assess the morphological nanostructure of the PDMS-chips. A confocal fluorescence analysis was utilized to check DNA distribution inside the chip.

  2. Determination of lidocaine in plasma by direct solid-phase microextraction combined with gas chromatography

    Koster, EHM; Wemes, C; Morsink, JB; de Jong, GJ


    Direct-immersion solid-phase microextraction (SPME) has been used to extract the local anesthetic lidocaine from human plasma. A simplified model shows the relationship between the total amount of drug in plasma and the amount of drug extracted. The model takes into account that the drug participate

  3. Direct potentiometric quantification of histamine using solid-phase imprinted nanoparticles as recognition elements.

    Basozabal, Itsaso; Guerreiro, Antonio; Gomez-Caballero, Alberto; Aranzazu Goicolea, M; Barrio, Ramón J


    A new potentiometric sensor based on molecularly imprinted nanoparticles produced via the solid-phase imprinting method was developed. For histamine quantification, the nanoparticles were incorporated within a membrane, which was then used to fabricate an ion-selective electrode. The use of nanoparticles with high affinity and specificity allowed for label-free detection/quantification of histamine in real samples with short response times. The sensor could selectively quantify histamine in presence of other biogenic amines in real wine and fish matrices. The limit of detection achieved was 1.12×10(-6)molL(-1), with a linear range between 10(-6) and 10(-2)molL(-1) and a response time below 20s, making the sensor as developed a promising tool for direct quantification of histamine in the food industry.

  4. Direct Numerical Simulation of Gas-Solid Two-Phase Mixing Layer

    Wenchun LI; Guilin HU; Zhe ZHOU; Jianren FAN; Kefa CEN


    In this paper, the spatially evolving of the higher Reynolds numbers gas-solid mixing layer under compressible conditions was investigated by a new direct numerical simulation technology. A high-resolution solver was performed for the gas-phase flow-field, particles with different Stokes numbers were traced by the Lagrangian approach based on one-way coupling. The processes of the vortex rolling up and pairing in the two-dimensional mixing layer were captured precisely. The large-scale structures developed from the initial inflow are characterized by the counter-rotating vortices. The mean velocity and the fluctuation intensities profiles agree well with the experimental data. Particles with smaller Stokes numbers accumulate at the vortex centers due to the smaller aerodynamic response time; particles with moderate Stokes numbers tend to orbit around individual streamwise vortices and in the periphery of paring vortices; particles with larger Stokes numbers disperse less evenly, showing a concentration distribution in the flow field.

  5. Direct MD simulation of liquid-solid phase equilibria for two-component plasmas

    Schneider, A S; Horowitz, C J; Berry, D K


    We determine the liquid-solid phase diagram for carbon-oxygen plasma mixtures using two-phase MD simulations. We identified liquid, solid, and interface regions using a bond angle metric. To study finite size effects, we perform 55296 ion simulations and compare to earlier 27648 ion results. To help monitor non-equilibrium effects, we calculate diffusion constants $D_i$. We find that $D_O$ for oxygen ions in the solid is much smaller than $D_C$ for carbon ions and that both diffusion constants are 80 or more times smaller than diffusion constants in the liquid phase. There is excellent agreement between our phase diagram and that predicted by Medin and Cumming. This suggests that errors from finite size and non-equilibrium effects are small and that the carbon-oxygen phase diagram is now accurately known.

  6. Direct determination of enthalpies of solid phase reactions by immersion method; Determination directe des enthalpies de reaction en phase solide par une methode de plongee

    Roux, A.; Richard, M.; Eyraud, L.; Stevanovic, M.; Elston, J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires


    It is not generally possible to measure the enthalpy change corresponding to solid phase reactions using the dynamic differential thermal analysis method because these reactions are usually too slow at the temperature of operation of present equipment. A ballistic differential thermal analysis apparatus has been developed which is based on an immersion-compensation method; it overcomes the difficulties previously encountered. This apparatus has been used after calibration for determining the enthalpies of formation of calcium and cadmium titanates. and also the Wigner energies of BeO, MgO and Al{sub 2}O{sub 3} samples irradiated at variable dose at a temperature of under 100 deg. C. (authors) [French] Il n'est generalement pas possible de mesurer la variation d'enthalpie correspondant aux reactions en phase solide par la methode d'analyse thermique differentielle dynamique. En effet, ces reactions sont le plus souvent trop lentes aux temperatures d'utilisation des dispositifs actuels. Un appareil d'analyse thermique differentielle balistique, base sur une methode de plongee avec compensation, a ete mis au point et permet de surmonter les difficultes precedentes. Apres etalonnages, cet appareil a ete utilise pour la determination des enthalpies de formation du titanate de calcium et du titanate de cadmium ainsi que pour celle des energies Wigner emmagasinees dans des echantillons de BeO, MgO et Al{sub 2}O{sub 3} irradies a une temperature inferieure a 100 deg. C et a differentes doses. (auteurs)

  7. Determination of crystal violet in water by direct solid phase spectrophotometry after rotating disk sorptive extraction.

    Manzo, Valentina; Navarro, Orielle; Honda, Luis; Sánchez, Karen; Inés Toral, M; Richter, Pablo


    The microextraction of crystal violet (CV) from water samples into polydimethylsiloxane (PDMS) using the rotating disk sorptive extraction (RDSE) technique was performed. The extracting device was a small Teflon disk that had an embedded miniature magnetic stirring bar and a PDMS (560 μL) film attached to one side of the disk using double-sided tape. The extraction involves a preconcentration of CV into the PDMS, where the analyte is then directly quantified using solid phase spectrophotometry at 600 nm. Different chemical and extraction device-related variables were studied to achieve the best sensitivity for the determination. The optimum extraction was performed at pH 14 because under this condition, CV is transformed to the neutral and colorless species carbinol, which can be quantitatively transferred to the PDMS phase. Although the colorless species is the chemical form extracted in the PDMS, an intense violet coloration appeared in the phase because the -OH bond in the carbinol molecule is weakened through the formation of hydrogen bonds with the oxygen atoms of the PDMS, allowing the resonance between the three benzene rings to compensate for the charge deficit on the central carbon atom of the molecule. The accuracy and precision of the method were evaluated in river water samples spiked with 10 and 30 μg L(-1) of CV, yielding a relative standard deviation of 6.2% and 8.4% and a recovery of 98.4% and 99.4%, respectively. The method detection limit was 1.8 μg L(-1) and the limit of quantification was 5.4 μg L(-1), which can be decreased if the sample volume is increased.

  8. Direct molecular dynamics simulation of liquid-solid phase equilibria for a three-component plasma.

    Hughto, J; Horowitz, C J; Schneider, A S; Medin, Zach; Cumming, Andrew; Berry, D K


    The neutron-rich isotope ²²Ne may be a significant impurity in carbon and oxygen white dwarfs and could impact how the stars freeze. We perform molecular dynamics simulations to determine the influence of ²²Ne in carbon-oxygen-neon systems on liquid-solid phase equilibria. Both liquid and solid phases are present simultaneously in our simulation volumes. We identify liquid, solid, and interface regions in our simulations using a bond angle metric. In general we find good agreement for the composition of liquid and solid phases between our MD simulations and the semianalytic model of Medin and Cumming. The trace presence of a third component, neon, does not appear to strongly impact the chemical separation found previously for two-component carbon and oxygen systems. This suggests that small amounts of ²²Ne may not qualitatively change how the material in white dwarf stars freezes. However, we do find systematically lower melting temperatures (higher Γ) in our MD simulations compared to the semianalytic model. This difference seems to grow with impurity parameter Q_{imp} and suggests a problem with simple corrections to the linear mixing rule for the free energy of multicomponent solid mixtures that is used in the semianalytic model.

  9. Direct molecular dynamics simulation of liquid-solid phase equilibria for two-component plasmas.

    Schneider, A S; Hughto, J; Horowitz, C J; Berry, D K


    We determine the liquid-solid phase diagram for carbon-oxygen and oxygen-selenium plasma mixtures using two-phase molecular dynamics simulations. We identify liquid, solid, and interface regions using a bond angle metric. To study finite-size effects, we perform 27,648- and 55,296-ion simulations. To help monitor nonequilibrium effects, we calculate diffusion constants D(i). For the carbon-oxygen system we find that D(O) for oxygen ions in the solid is much smaller than D(C) for carbon ions and that both diffusion constants are 80 or more times smaller than diffusion constants in the liquid phase. There is excellent agreement between our carbon-oxygen phase diagram and that predicted by Medin and Cumming. This suggests that errors from finite-size and nonequilibrium effects are small and that the carbon-oxygen phase diagram is now accurately known. The oxygen-selenium system is a simple two-component model for more complex rapid proton capture nucleosynthesis ash compositions for an accreting neutron star. Diffusion of oxygen, in a predominantly selenium crystal, is remarkably fast, comparable to diffusion in the liquid phase. We find a somewhat lower melting temperature for the oxygen-selenium system than that predicted by Medin and Cumming. This is probably because of electron screening effects.

  10. Direct solid-phase microextraction combined with gas and liquid chromatography for the determination of lidocaine in human urine

    Koster, E.H M; Hofman, N.S K; de Jong, G.J.


    Solid-phase microextraction (SPME) has been combined with gas chromatography (GC) and liquid chromatography (LC) for the determination of lidocaine in human urine. A polydimethylsiloxane (PDMS) coated fibre was directly immersed into buffered urine. Extraction conditions such as time, pH, ionic stre

  11. Direct MD simulation of liquid-solid phase equilibria for three-component plasma

    Hughto, J; Schneider, A S; Medin, Zach; Cumming, Andrew; Berry, D K


    The neutron rich isotope 22Ne may be a significant impurity in carbon and oxygen white dwarfs and could impact how the stars freeze. We perform molecular dynamics simulations to determine the influence of 22Ne in carbon-oxygen-neon systems on liquid-solid phase equilibria. Both liquid and solid phases are present simultaneously in our simulation volumes. We identify liquid, solid, and interface regions in our simulations using a bond angle metric. In general we find good agreement for the composition of liquid and solid phases between our MD simulations and the semi analytic model of Medin and Cumming. The trace presence of a third component, neon, does not appear to strongly impact the chemical separation found previously for two component carbon and oxygen systems. This suggests that small amounts of 22Ne may not qualitatively change how the material in white dwarf stars freezes. However, we do find systematically lower melting temperatures (higher Gamma) in our MD simulations compared to the semi analytic ...

  12. Feasibility of the direct coupling of solid-phase extraction-pipette tips with a programmed-temperature vaporiser for gas chromatographic analysis of drugs in plasma

    van Hout, M.W J; van Egmond, W.M A; Franke, J.P.; de Zeeuw, R.A; de Jong, G.J.


    Solid-phase extraction-pipette tips (SPE-PTs) were used for micro solid-phase extraction of lidocaine and diazepam from plasma. Off-line extraction was followed by on-line desorption. On-line desorption was carried out by direct coupling of the SPE-PTs with the liner of the programmed-temperature va

  13. Rotating disk sorbent extraction for pre-concentration of chromogenic organic compounds and direct determination by solid phase spectrophotometry.

    Richter, Pablo; Cañas, Alejandro; Muñoz, Carlos; Leiva, Claudio; Ahumada, Inés


    A novel and very simple microextraction approach for pre-concentration and direct solid phase spectrophotometric measurement has been developed for the determination of chromogenic analytes. The model analyte to assess this approach was the chromophore malachite green (MG). The analyte was extracted from water samples onto a small rotating disk made of Teflon containing a sorbent phase of polydimethylsiloxane (PDMS) on one of its surfaces. We refer to the extraction procedure as rotating disk sorptive extraction (RDSE). After extraction, the sorbent phase with the concentrated analyte was separated from the Teflon disk and used directly for MG determination by solid phase spectrophotometry at 624 nm, without the necessity of a desorption step. Chemical and extraction variables such as concentration of sodium sulfate, pH, disk rotational velocity, extraction time, and temperature were studied in order to establish the best conditions for extraction. Under optimum conditions, the extraction of MG was carried out in 18 min and 90 min, for sample volumes of 100mL or 1000 mL, respectively. The detection limit, based on three times the standard deviation of the blank phase (3σ(b)), was 1.4 μg L⁻¹ and the repeatability, expressed as relative standard deviation (RSD), for 20 μg L⁻¹ MG was 8.1%. This study also applied the method to real samples, obtaining quantitative recovery (mean recovery of 99.3%). The PDMS phases could be reused after desorbing the MG into methanol for 3h. Replacement of the PDMS film onto the disk is very easy and low cost.

  14. Direct tandem mass spectrometric analysis of amino acids in plasma using fluorous derivatization and monolithic solid-phase purification.

    Tamashima, Erina; Hayama, Tadashi; Yoshida, Hideyuki; Imakyure, Osamu; Yamaguchi, Masatoshi; Nohta, Hitoshi


    In this study, we developed a novel direct tandem mass spectrometric method for rapid and accurate analysis of amino acids utilizing a fluorous derivatization and purification technique. Amino acids were perfluoroalkylated with 2H,2H,3H,3H-perfluoroundecan-1-al in the presence of 2-picoline borane via reductive amination. The derivatives were purified by perfluoroalkyl-modified silica-based monolithic solid-phase extraction (monolithic F-SPE), and directly analyzed by tandem mass spectrometry using electrospray ionization without liquid chromatographic separation. The perfluoroalkyl derivatives could be sufficiently distinguished from non-fluorous compounds, i.e. the biological matrix, due to their fluorous interaction. Thus, rapid and accurate determination of amino acids was accomplished. The method was validated with human plasma samples and applied to the analysis of amino acids in the plasma of mice with maple syrup urine disease or phenylketonuria.

  15. Solid phase transformations II

    Čermák, J


    This topical volume includes ten invited papers that cover selected areas of the field of solid phase transformations. The first two contributions represent a burgeoning branch; that of the computer simulation of physical phenomena. The following three articles deal with the thermodynamics of phase transformations as a basic theory for describing the phenomenology of phase changes in matter. The next paper describes the interconnections between structural stability and the electronic structure of phases. Two further articles are devoted to displacive transformations; a field where there are ma

  16. Solid-phase microextraction

    Nilsson, Torben

    The objective of this study has been to develop new analytical methods using the rapid, simple and solvent-free extraction technique solid-phase microextraction (SPME) for the quantitative analysis of organic pollutants at trace level in drinking water and environmental samples. The dynamics...

  17. Solid phases of tenoxicam.

    Cantera, Rodrigo G; Leza, María G; Bachiller, Carmen M


    In this report we describe the preparation and characterization of four polymorphic forms of tenoxicam; they are, three 1:1 stoichiometric solvates with acetonitrile, dioxane, and N,N-dimethylformamide, and an amorphous phase obtained by recrystallization in various solvents. Polymorph IV and solvates with dioxane and N,N-dimethylformamide are reported for the first time in this paper. In addition, three solvates were crystallized in acetone, ethyl acetate, and isopropyl alcohol. These solid forms were characterized by X-ray powder diffraction, differential scanning calorimetry, infrared spectroscopy, thermogravimetry, optical microscopy, and elemental analysis. Solid-state properties, intrinsic dissolution rate, and dissolution kinetics from formulated tablets are also provided.

  18. Direct Sampling and Analysis from Solid Phase Extraction Cards using an Automated Liquid Extraction Surface Analysis Nanoelectrospray Mass Spectrometry System

    Walworth, Matthew J [ORNL; ElNaggar, Mariam S [ORNL; Stankovich, Joseph J [ORNL; WitkowskiII, Charles E. [Protein Discovery, Inc.; Norris, Jeremy L [ORNL; Van Berkel, Gary J [ORNL


    Direct liquid extraction based surface sampling, a technique previously demonstrated with continuous flow and autonomous pipette liquid microjunction surface sampling probes, has recently been implemented as the Liquid Extraction Surface Analysis (LESA) mode on the commercially available Advion NanoMate chip-based infusion nanoelectrospray ionization system. In the present paper, the LESA mode was applied to the analysis of 96-well format custom solid phase extraction (SPE) cards, with each well consisting of either a 1 or 2 mm diameter monolithic hydrophobic stationary phase. These substrate wells were conditioned, loaded with either single or multi-component aqueous mixtures, and read out using the LESA mode of a TriVersa NanoMate or a Nanomate 100 coupled to an ABI/Sciex 4000QTRAPTM hybrid triple quadrupole/linear ion trap mass spectrometer and a Thermo LTQ XL linear ion trap mass spectrometer. Extraction conditions, including extraction/nanoESI solvent composition, volume, and dwell times, were optimized in the analysis of targeted compounds. Limit of detection and quantitation as well as analysis reproducibility figures of merit were measured. Calibration data was obtained for propranolol using a deuterated internal standard which demonstrated linearity and reproducibility. A 10x increase in signal and cleanup of micromolar Angiotensin II from a concentrated salt solution was demonstrated. Additionally, a multicomponent herbicide mixture at ppb concentration levels was analyzed using MS3 spectra for compound identification in the presence of isobaric interferences.

  19. Solid phase transformations

    Čermák, J


    This special-topic book, devoted to ""Solid Phase Transformations"" , covers a broad range of phenomena which are of importance in a number of technological processes. Most commercial alloys undergo thermal treatment after casting, with the aim of imparting desired compositions and/or optimal morphologies to the component phases. In spite of the fact that the topic has lain at the center of physical metallurgy for a long time, there are numerous aspects which are wide open to potential investigative breakthroughs. Materials with new structures also stimulate research in the field, as well as n

  20. Hydrophobic coating of polyaniline-poly(propylene oxide) copolymer for direct immersion solid phase microextraction of carbamate pesticides.

    Ai, Youhong; Zhang, Jingqiang; Zhao, Faqiong; Zeng, Baizhao


    A nanostructural polyaniline-poly(propylene oxide) (PANI-PPO) composite coating was electrochemically synthesized on a stainless steel wire, by using acidic ionic liquid 1-sulfobutyl-3-methylimidazolium hydrosulfate as supporting electrolyte. The coating showed strong hydrophobicity and allowed for the direct immersion solid-phase microextraction of carbamate pesticides (i.e. 2-(1-methylethoxy) phenyl methylcarbamate, m-tolyl-n-methylcarbamate, 2-(1-methylethyl) phenyl methylcarbamate, 2-(1-methylpropyl) phenol methylcarbamate and 2,3-dihydro-2,2-dimethyl-7-benzofuranyl methylcarbamate) in complex matrices. Moreover, this coating could be used for at least 120 times of extraction. When it was coupled with gas chromatography for the determination of these carbamate pesticides the linear ranges were about 0.1-100 μg L(-1) and the detection limits were 0.012-0.048 μg L(-1). It also displayed acceptable repeatability and reproducibility. When a fiber was used for five successive measurements the relative standard deviations (RSDs) were smaller than 8.7%, and the RSDs for fiber-to-fiber were 5.7-12.9% (n=5). The practical feasibility of the proposed method was evaluated by determining carbamate pesticides in vegetable samples and the recoveries for standards added were 79.8-108.8%. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Directional anisotropy of magnetostriction and magnetic phase transition in Nd14 Dy2 Fe78 B6 solid solution

    N. T.


    Full Text Available   In this research. The magnetic phase transition and anisotropic magnetoelastic effects of a polycrystalline sample of Nd14Dy2Fe78B6 were studied by susceptibility and magnetostriction measurements. The composition was prepared by casting method. SEM pictures and XRD analysis showed that it was composed of polycrystalline magnetic phases with the main phase of 2-14-1. Results of ac susceptibility measurements show that the sample undergoes a magnetic phase transition at about 130 K, which is due to a gradual spin reorientaion accompanied with crystal structure distortion. Magnetostriction measurements in three orthogonal directions of the main body of the sample were performed in the range of 77 K to 300 K and in the field up to 1.5 T. At temperatures below 125 K, the magnetostriction values in three orthogonal directions differ by a factor of two to three. This anisotropy in magnetostriction indicates preferential orientation of the crystalline grains in the volume of the sample. In addition, magnetostriction curves show minimum values near the phase transition temperature with different values in the different directions. Minimum values of magnetostriction can be explained by the critical behavior of the orbital magnetic moments of the Fe atoms at the phase transition temperature.

  2. A comparison of observables for solid-solid phase transitions

    Smilowitz, Laura B [Los Alamos National Laboratory; Henson, Bryan F [Los Alamos National Laboratory; Romero, Jerry J [Los Alamos National Laboratory


    The study of solid-solid phase transformations is hindered by the difficulty of finding a volumetric probe to use as a progress variable. Solids are typically optically opaque and heterogeneous. Over the past several years, second harmonic generation (SHG) has been used as a kinetic probe for a solid-solid phase transition in which the initial and final phases have different symmetries. Bulk generation of SHG is allowed by symmetry only in noncentrosymmetric crystallographic space groups. For the organic energetic nitramine octahydro-1,3 ,5,7 -tetranitro-1,3 ,5,7 -tatrazocine (HMX), the beta phase is centro symmetric (space group P2{sub 1}/c) and the delta phase iS noncentrosymmetric (space group P6{sub 1}22) making SHG an extremely sensitive, essentially zero background probe of the phase change progress. We have used SHG as a tool to follow the progress of the transformation from beta to delta phase during the solid-solid transformation. However, kinetic models of the transformation derived using different observables from several other groups have differed, showing later onset for the phase change and faster progression to completion. In this work, we have intercompared several techniques to understand these differences. The three techniques discussed are second harmonic generation, Raman spectroscopy, and differential scanning calorimetry (DSC). The progress of the beta to delta phase transition in HMX observed with each of these different probes will be discussed and advantages and disadvantages of each technique described. This paper compares several different observables for use in measuring the kinetics of solid-solid phase transitions. Relative advantages and disadvantages for each technique are described and a direct comparison of results is made for the beta to delta polymorphic phase transition of the energetic nitramine, octahydro-1,3,5,7-tetranitro-1,3,5,7-tatrazocine.

  3. Solid phase syntheses of oligoureas

    Burgess, K.; Linthicum, D.S.; Russell, D.H.; Shin, H.; Shitangkoon, A.; Totani, R.; Zhang, A.J.; Ibarzo, J. [Texas A& M Univ., College Station, TX (United States)


    Isocyanates 7 were formed from monoprotected diamines 3 or 6, which in turn can be easily prepared from commercially available N-BOC- or N-FMOC-protected amino acid derivatives. Isocyanates 7, formed in situ, could be coupled directly to a solid support functionalized with amine groups or to amino acids anchored on resins using CH{sub 2}Cl{sub 2} as solvent and an 11 h coupling time at 25 {degree}C. Such couplings afforded peptidomimetics with an N-phthaloyl group at the N-terminus. The optimal conditions identified for removal of the N-phthaloyl group were to use 60% hydrazine in DMF for 1-3 h. Several sequences of amino acids coupled to ureas (`peptidic ureas`) and of sequential urea units (`oligoureas`) were prepared via solid phase syntheses and isolated by HPLC. Partition coefficients were measured for two of these peptidomimetics, and their water solubilities were found to be similar to the corresponding peptides. A small library of 160 analogues of the YGGFL-amide sequence was prepared via Houghten`s tea bag methodology. This library was tested for binding to the anti-{beta}-endorphin monoclonal antibody. Overall, this paper describes methodology for solid phase syntheses of oligourea derivatives with side chains corresponding to some of the protein amino acids. The chemistry involved is ideal for high-throughput syntheses and screening operations. 51 refs., 3 figs., 2 tabs.

  4. Ultrathin GeSn p-channel MOSFETs grown directly on Si(111) substrate using solid phase epitaxy

    Maeda, Tatsuro; Jevasuwan, Wipakorn; Hattori, Hiroyuki; Uchida, Noriyuki; Miura, Shu; Tanaka, Masatoshi; Santos, Nuno D. M.; Vantomme, André; Locquet, Jean-Pierre; Lieten, Ruben R.


    Ultrathin GeSn layers with a thickness of 5.5 nm are fabricated on a Si(111) substrate by solid phase epitaxy (SPE) of amorphous GeSn layers with Sn concentrations up to 6.7%. We demonstrate well-behaved depletion-mode operation of GeSn p-channel metal-oxide-semiconductor field-effect transistors (pMOSFETs) with an on/off ratio of more than 1000 owing to the ultrathin GeSn channel layer (5.5 nm). It is found that the on current increases significantly with increasing Sn concentration at the same gate overdrive, attributed to an increasing substitutional Sn incorporation in Ge. The GeSn (6.7%) layer sample shows approximately 90% enhancement in hole mobility in comparison with a pure Ge channel on Si.

  5. Solid-phase synthesis of a 6-phenylquinolin-2(1H)-one library directed toward nuclear hormone receptors.

    Ruda, Marcus; Kann, Nina; Gordon, Sandra; Bergman, Jan; Nelson, William; Agback, Peter; Hagberg, Lars; Koehler, Konrad F


    A library of 6-phenylquinolin-2(1H)-ones with diversity at position 1 and the ortho, meta, and para positions of the pendant phenyl ring has been synthesized using solid-phase parallel synthetic techniques. A key step in the synthesis of the library is a tandem alkylation cleavage in which diversity can be introduced at position 1 simultaneously to the cleavage from the resin. The yields of this step were significantly improved over what has previously been reported by addition of cesium carbonate to scavenge the acid that is formed during the reaction. Furthermore, we have shown that the solid support linkage is tolerant to Suzuki coupling and etherification reaction conditions and that selective cleavage of the linkage can take place in the presence of esters. The resulting 6-phenylquinolin-2(1H)-one library was screened against a panel of nuclear hormone receptors (androgen, estrogen alpha and beta isoforms, glucocorticoid, mineralocorticoid, and progesterone). Certain members of this library display moderate affinity for several of these receptors, and consequently, the 6-phenylquinolin-2(1H)-one core of the library may be considered a privileged structure for nuclear hormone receptors. In contrast, other members of the library display high selectivity for a particular receptor. The highest affinity ligand (9{2,1,1}) possesses an affinity of 330 nM for the androgen receptor, whereas the most selective ligand (9{2,4,1}) displays an affinity of 900 nM for the androgen receptor and a selectivity of 140-fold over the next highest affinity receptor.

  6. Solid-Phase Random Glycosylation

    Agoston, K.; Kröger, Lars; Dekany, Gyula


    Two different approaches were employed to study solid phase random glycosylations to obtain oligosaccharide libraries. In approach I, Wang resin esters were attached to the acceptors structures. Following their glycosylation and resin cleavage, the peracetylated components of the oligosaccharide ...

  7. Solid-phase peptide synthesis

    Jensen, Knud Jørgen


    This chapter provides an introduction to and overview of peptide chemistry with a focus on solid-phase peptide synthesis. The background, the most common reagents, and some mechanisms are presented. This chapter also points to the different chapters and puts them into perspective.......This chapter provides an introduction to and overview of peptide chemistry with a focus on solid-phase peptide synthesis. The background, the most common reagents, and some mechanisms are presented. This chapter also points to the different chapters and puts them into perspective....

  8. Statistical Thermodynamics of an "Open" Hard Sphere System on the Equilibrium Fluid Isotherm: Study of Properties of the Freezing Transition Without Direct Involvement of the Equilibrium Solid Phase

    Reiss, Howard; Manzanares, José A.


    Using several theoretical toolsldots (i) the nucleation theorem, (ii) an equivalent cavity, (iii) the reversible work of adding a cavity to an open hard sphere system, and (iv) the theory of "stability"... the authors estimated the density at which the hard sphere freezing transition occurs. No direct involvement of the equilibrium solid phase is involved. The reduced density \\uppi a^3ρ _f/6 (where a is the hard sphere diameter and ρ _f is the actual density at which freezing occurs) is found to be 0.4937 while the value obtained by computer simulation is 0.494. The agreement is good, but the new method still contains some approximation. However, the approximation is based on the idea that at a density just below ρ _f the fluid adopts a distorted structure resembling the solid, but different enough so that long-range order vanishes. Initial loss of stability may not be involved in every fluid-solid transition, but it may be an early step in the hard sphere and related systems.



    The solid-phase synthesis of isoxazolines on 2-polystyrylsulfonamidoethanol resin isreported. 2-Polystyrylsuifonamidoethanol resin 1 was reacted with acryloyl chloride to afford2-polystyrylsulfonylamidoethyl acrylate resin 2, which was further reacted with brominatedaldoximes by [3+2] cycioaddition to give isoxazoline resin 4. Resin 4 was treated with aqueous 6mol/L HCI solution to obtain isoxazolines in good yield and purity.

  10. Multiple solid-phase microextraction

    Koster, EHM; de Jong, GJ


    Theoretical aspects of multiple solid-phase microextraction are described and the principle is illustrated with the extraction of lidocaine from aqueous solutions. With multiple extraction under non-equilibrium conditions considerably less time is required in order to obtain an extraction yield that

  11. Solid sampling electrothermal vaporization inductively coupled plasma mass spectrometry for the direct determination of Hg in different materials using isotope dilution with a gaseous phase for calibration

    Resano, M.; Gelaude, I.; Dams, R.; Vanhaecke, F.


    This paper evaluates the potential of electrothermal vaporization-inductively coupled plasma mass spectrometry (ETV-ICPMS) for the direct determination of Hg in solid samples, using a 200Hg-enriched gaseous phase for calibration based on isotope dilution. Three different samples were studied, BCR CRM 320 River sediment, IAEA-086 Hair and a real (wet) freshwater fish sample (M1). The samples selected show important differences in their matrix composition, and especially the fish sample constitutes a challenge as a result of its high water content (≈80%). The main conclusion of the work is that the calibration approach investigated succesfully corrects for all the matrix effects (suppression) observed during Hg vaporization, allowing accurate values to be obtained in all cases. Moreover, practically the same operating conditions could be used for all sample types. The method finally proposed presents interesting features for the direct determination of this challenging element in solid samples, such as: a low sample consumption (a few milligrams), a high sample throughput (10 min/sample), a low limit of detection (6 ng g -1) and a reduced risk of analyte losses or contamination. Precision values depend on the homogeneity of the sample studied, and are typically in the vicinity of 10% RSD, except for the more inhomogenous river sediment (18% RSD).

  12. Direct modification of hydrogen/deuterium-terminated diamond particles with polymers to form reversed and strong cation exchange solid phase extraction sorbents.

    Yang, Li; Jensen, David S; Vail, Michael A; Dadson, Andrew; Linford, Matthew R


    We describe direct polymer attachment to hydrogen and deuterium-terminated diamond (HTD and DTD) surfaces using a radical initiator (di-tert-amyl peroxide, DTAP), a reactive monomer (styrene) and a crosslinking agent (divinylbenzene, DVB) to create polystyrene encapsulated diamond. Chemisorbed polystyrene is sulfonated with sulfuric acid in acetic acid. Surface changes were followed by X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS) and diffuse reflectance Fourier transform infrared spectroscopy (DRIFT). Finally, both polystyrene-modified DTD and sulfonated styrene-modified DTD were used in solid phase extraction (SPE). Percent recovery and column capacity were investigated for both phenyl (polystyrene) and sulfonic acid treated polystyrene SPE columns. These diamond-based SPE supports are stable under basic conditions, which is not the case for silica-based SPE supports.

  13. A phase I, dose-escalation study of TB-403, a monoclonal antibody directed against PlGF, in patients with advanced solid tumours

    Lassen, U; Nielsen, D L; Sørensen, M


    , dyspnoea, and nausea. One serious AE, a lung embolus in a patient with non-small cell lung cancer treated with 10 mg kg(-1) weekly, was deemed possibly related to TB-403. No dose-limiting toxicities were observed, and a maximum-tolerated dose was not reached. The PK parameters were dose linear...... and the terminal half-life values ranged from 9 to 14 days. Six patients exhibited stable disease for at least 8 weeks. Two patients, (oesophageal squamous cell carcinoma and pancreatic adenocarcinoma) both treated with 5 mg kg(-1) weekly, remained stable for 12 months. CONCLUSION: TB-403 treatment in this patient......BACKGROUND: TB-403 (RO 5323441), a humanised monoclonal antibody, is a novel antiangiogenesis agent directed against placental growth factor. The safety, pharmacokinetics (PK), and antitumour activity of TB-403 were assessed in a phase I, dose-escalation study in patients with advanced solid...

  14. Fast analysis of glycosides based on HKUST-1-coated monolith solid-phase microextraction and direct analysis in real-time mass spectrometry.

    Li, Xianjiang; Wang, Xin; Ma, Wen; Ai, Wanpeng; Bai, Yu; Ding, Li; Liu, Huwei


    Glycosides are a kind of highly important natural aromatic precursors in tobacco leaves. In this study, a novel HKUST-1-coated monolith dip-it sampler was designed for the fast and sensitive analysis of trace glycosides using direct analysis in real-time mass spectrometry. This device was prepared in two steps: in situ polymerization of monolith in a glass capillary of dip-it and layer-by-layer growth of HKUST-1 on the surface of monolith. Sufficient extraction was realized by immersing the tip to solution and in situ desorption was carried out by plasma direct analysis in real time. Compared with traditional solid-phase microextraction protocols, sample desorption was not needed anymore, and only extraction conditions were needed to be optimized in this method, including the gas temperature of direct analysis in real time, extraction time, and CH3 COONH4 additive concentration. This method enabled the simultaneous detection of six kinds of glycosides with the limits of detection of 0.02-0.05 μg/mL and the linear ranges covering two orders of magnitude with the limits of quantitation of 0.05-0.1 μg/mL. Moreover, the developed method was applied for the glycosides analysis of three tobacco samples, which only took about 2 s for every sample.


    SUNWeimin; LUOJuntao; 等


    The solid-phase synthesis of isoxazolines on 2-polystyrylsulfonamidoethanol resin is reported.2-Polystyrylsulfonamidoethanol resin 1 was reacted with acryloyl chloride to afford 2-polystyrylsulfonylamidoethyl acrylate resin 2,which was further reacted with brominated aldoximes by [3+2] cycloaddition to give isoxazoline resin 4.Resin 4 was treated with aqueous 6 mol/L HCl solution to obtain isoxazolines in good yield and purity.

  16. Seeing Below the Drop: Direct Nano-to-microscale Imaging of Complex Interfaces involving Solid, Liquid, and Gas Phases

    Rykaczewski, Konrad; Landin, Trevan; Walker, Marlon L.; Scott, John Henry J.; Varanasi, Kripa K.


    Nanostructured surfaces with special wetting properties have the potential to transform number of industries, including power generation, water desalination, gas and oil production, and microelectronics thermal management. Predicting the wetting properties of these surfaces requires detailed knowledge of the geometry and the composition of the contact volume linking the droplet to the underlying substrate. Surprisingly, a general nano-to-microscale method for direct imaging of such interfaces has previously not been developed. Here we introduce a three dimensional imaging method which resolves this one-hundred-year-old metrology gap in wetting research. Specifically, we demonstrate direct nano-to-microscale imaging of complex fluidic interfaces using cryofixation in combination with cryo-FIB/SEM. We show that application of this method yields previously unattainable quantitative information about the interfacial geometry of water condensed on silicon nanowire forests with hydrophilic and hydrophobic surface termination in the presence or absence of an intermediate water repelling oil. We also discuss imaging artifacts and the advantages of secondary and backscatter electron imaging, Energy Dispersive Spectrometry (EDS), and three dimensional FIB/SEM tomography.

  17. Multiplexed Colorimetric Solid-Phase Extraction

    Gazda, Daniel B.; Fritz, James S.; Porter, Marc D.


    Multiplexed colorimetric solid-phase extraction (MC-SPE) is an extension of colorimetric solid-phase extraction (C-SPE) an analytical platform that combines colorimetric reagents, solid phase extraction, and diffuse reflectance spectroscopy to quantify trace analytes in water. In CSPE, analytes are extracted and complexed on the surface of an extraction membrane impregnated with a colorimetric reagent. The analytes are then quantified directly on the membrane surface using a handheld diffuse reflectance spectrophotometer. Importantly, the use of solid-phase extraction membranes as the matrix for impregnation of the colorimetric reagents creates a concentration factor that enables the detection of low concentrations of analytes in small sample volumes. In extending C-SPE to a multiplexed format, a filter holder that incorporates discrete analysis channels and a jig that facilitates the concurrent operation of multiple sample syringes have been designed, enabling the simultaneous determination of multiple analytes. Separate, single analyte membranes, placed in a readout cartridge create unique, analyte-specific addresses at the exit of each channel. Following sample exposure, the diffuse reflectance spectrum of each address is collected serially and the Kubelka-Munk function is used to quantify each water quality parameter via calibration curves. In a demonstration, MC-SPE was used to measure the pH of a sample and quantitate Ag(I) and Ni(II).

  18. Determination of phthalate esters in vegetable oils using direct immersion solid-phase microextraction and fast gas chromatography coupled with triple quadrupole mass spectrometry.

    Barp, Laura; Purcaro, Giorgia; Franchina, Flavio A; Zoccali, Mariosimone; Sciarrone, Danilo; Tranchida, Peter Q; Mondello, Luigi


    Phthalates are a group of synthetic compounds mainly used as plasticizers, which have been classified as endocrine-disrupting chemicals and potential human-cancer causing agents. They can be found in high amounts in foods, deriving mainly from plastic packaging. The analytical determination of these compounds is very challenging since they are ubiquitous. Therefore, minimization of sample manipulation is highly desirable. The present work exploited the application of a solid-phase microextraction method for the analysis of phthalates in vegetable oil. A preliminary comparison between a polydimethylsiloxane (PDMS) and a Carbopack Z/PDMS fiber was carried out both in the headspace and direct immersion extraction modes. Before immersing the fiber, a rapid liquid-liquid extraction was performed using acetonitrile to remove the bulk of triglycerides. PDMS in the direct immersion mode showed the best performance. The method was fully validated obtaining a good linearity with a coefficient of correlation of over 0.9960 for all compounds, repeatability and accuracy values generally better than 10%, and very good limit of quantification values.

  19. Solid Phase Characterization of Solids Recovered from Failed Sluicer Arm

    Cooke, Gary A. [Hanford Site (HNF), Richland, WA (United States)


    The Enclosure to this memo discusses the solid phase characterization of a solid sample that was retrieved from the single-shell Tank 241-C-111 extended reach sluicer #2. This sluicer, removed from riser #3 on September 25, 2014, was found to have approximately 0.4 gallons of solid tank waste adhering to the nozzle area.

  20. Density-functional theory for fluid-solid and solid-solid phase transitions

    Bharadwaj, Atul S.; Singh, Yashwant


    We develop a theory to describe solid-solid phase transitions. The density functional formalism of classical statistical mechanics is used to find an exact expression for the difference in the grand thermodynamic potentials of the two coexisting phases. The expression involves both the symmetry conserving and the symmetry broken parts of the direct pair correlation function. The theory is used to calculate phase diagram of systems of soft spheres interacting via inverse power potentials u (r ) =ɛ "close="1 /n )">σ /r n , where parameter n measures softness of the potential. We find that for 1 /n ≥0.154 the body-centred-cubic (bcc) structure is preferred. The bcc structure transforms into the fcc structure upon increasing the density. The calculated phase diagram is in good agreement with the one found from molecular simulations.

  1. Direct determination of acrylamide in potato chips by using headspace solid-phase microextraction coupled with gas chromatography-flame ionization detection.

    Ghiasvand, Ali Reza; Hajipour, Somayeh


    Acrylamide is a potentially toxic and carcinogenic substance present in many high-consumption foods. Recently, this matter has been placed in category of "reasonably anticipated to be a human carcinogen" by National Toxicology Program (NTP). Therefore, simple and cost-effective determination of acrylamide in food samples has attracted intense interest. The most reported techniques for this purpose are GC-MS and LC-MS, which are very expensive and available in few laboratories. In this research, for the first time, a rapid, easy and low-cost method is introduced for sensitive and precise determination of acrylamide in foodstuffs, using gas chromatography-flame ionization detection (GC-FID) system after its direct trapping in the upper atmosphere of samples by headspace solid-phase microextraction (HS-SPME). The effects of main experimental variables were studied and the optimized parameters were obtained as the type of fiber, carboxen/divinylbenzene/polydimethylsiloxane (CAR/DVB/PDMS); extraction time, 30 min; extraction temperature, 60°C; moisture content, 10 µL water per 1g of sample; desorption time, 2 min; and desorption temperature, 230°C. The linear calibration graph was obtained in the range of 0.77-50 µg g(-1), with regression coefficient of 0.998. The detection and quantification limits of the proposed method were 0.22 and 0.77 µg g(-1), respectively. The recoveries, for different food samples, were 79.6-95.7%. The repeatability of measurements, expressed as relative standard deviation (RSD), were found to be 4.1-8.0% (n=9). The proposed HS-SPME-GC-FID method was successfully carried out for quantifying of trace levels of acrylamide in some processed food products (chips and French fries), sold in open local markets.

  2. Direct speciation analysis of thallium based on solid phase extraction and specific retention of a Tl(III) complex on alumina coated with sodium dodecyl sulfate.

    Biaduń, Ewa; Sadowska, Monika; Ospina-Alvarez, Natalia; Krasnodębska-Ostręga, Beata

    Alumina (Al2O3) with an average particle size of 63 μm was modified with the anionic surfactant sodium dodecyl sulfate (SDS) and then applied to (i) solid phase extraction and separation of both thallium(I) and thallium(III), and (ii) preconcentration of Tl(III) from waste water samples. Only Tl(III), in the form of its complex with diethylenetriaminepentaacetate (DTPA), was retained on the sorbent, from where it can be eluted with 40 % nitric acid. Thallium species were then quantified by ICP MS. The method was characterized by a LOD of 25 pg of Tl(I) and 160 pg of Tl(III) in 10 mL samples. A large excesses of Tl(I) over Tl(III) was tolerated, and relatively high levels of other metal ions, such as a 500-fold excess of Pb(II) and Cd(II), and a 2000-fold excess of Zn(II), respectively, do not interfere. The sorbent was easily prepared and possesses a high loading capacity, and these properties make it an attractive material for rapid and efficient extraction and speciation of Tl. Graphical abstract:Schematic of the SPE procedure for separation (with preconcentration) of Tl(III) from Tl(I) was developed and applied to direct speciation analysis of thallium in wastewater. Self-made columns packed with alumina coated with SDS were used. The method is resistant to interferences from Pb, Cd, Zn and tolerates a large excess of Tl(I) over Tl(III).



    Velocities of solid phase and liquid phase in debris flow are one key problem to research on impact and abrasion mechanism of banks and control structures under action of debris flow. Debris flow was simplified as two-phase liquid composed of solid phase with the same diameter particles and liquid phase with the same mechanical features. Assume debris flow was one-dimension two-phase liquid moving to one direction,then general equations of velocities of solid phase and liquid phase were founded in twophase theory. Methods to calculate average pressures, volume forces and surface forces of debris flow control volume were established. Specially, surface forces were ascertained using Bingham's rheology equation of liquid phase and Bagnold's testing results about interaction between particles of solid phase. Proportional coefficient of velocities between liquid phase and solid phase was put forward, meanwhile, divergent coefficient between theoretical velocity and real velocity of solid phase was provided too. To state succinctly before, method to calculate velocities of solid phase and liquid phase was obtained through solution to general equations. The method is suitable for both viscous debris flow and thin debris flow. Additionally, velocities every phase can be identified through analyzing deposits in-situ after occurring of debris flow. It is obvious from engineering case the result in the method is consistent to that in real-time field observation.

  4. Directed solid-phase synthesis of trisubstituted imidazo[4,5-c]pyridines and imidazo[4,5-b]pyridines.

    Lemrová, Barbora; Smyslová, Petra; Popa, Igor; Oždian, Tomáš; Zajdel, Pawel; Soural, Miroslav


    An efficient method is described for the solid-supported synthesis of imidazo[4,5-b]pyridines and imidazo[4,5-c]pyridines from 2,4-dichloro-3-nitropyridine. The key pyridine building block was reacted with polymer-supported amines, followed by replacement of the second chlorine with amines, nitro group reduction, and imidazole ring closure with aldehydes. Depending on the combination of polymer-supported and solution-phase reagents, the strategy allowed for the simple preparation of the target trisubstituted derivatives with variable positioning of the pyridine nitrogen atom. Additionally, after a slight modification of the method, the preparation of strictly isomeric imidazopyridines was possible.

  5. Parameters optimization using experimental design for headspace solid phase micro-extraction analysis of short-chain chlorinated paraffins in waters under the European water framework directive.

    Gandolfi, F; Malleret, L; Sergent, M; Doumenq, P


    The water framework directives (WFD 2000/60/EC and 2013/39/EU) force European countries to monitor the quality of their aquatic environment. Among the priority hazardous substances targeted by the WFD, short chain chlorinated paraffins C10-C13 (SCCPs), still represent an analytical challenge, because few laboratories are nowadays able to analyze them. Moreover, an annual average quality standards as low as 0.4μgL(-1) was set for SCCPs in surface water. Therefore, to test for compliance, the implementation of sensitive and reliable analysis method of SCCPs in water are required. The aim of this work was to address this issue by evaluating automated solid phase micro-extraction (SPME) combined on line with gas chromatography-electron capture negative ionization mass spectrometry (GC/ECNI-MS). Fiber polymer, extraction mode, ionic strength, extraction temperature and time were the most significant thermodynamic and kinetic parameters studied. To determine the suitable factors working ranges, the study of the extraction conditions was first carried out by using a classical one factor-at-a-time approach. Then a mixed level factorial 3×2(3) design was performed, in order to give rise to the most influent parameters and to estimate potential interactions effects between them. The most influent factors, i.e. extraction temperature and duration, were optimized by using a second experimental design, in order to maximize the chromatographic response. At the close of the study, a method involving headspace SPME (HS-SPME) coupled to GC/ECNI-MS is proposed. The optimum extraction conditions were sample temperature 90°C, extraction time 80min, with the PDMS 100μm fiber and desorption at 250°C during 2min. Linear response from 0.2ngmL(-1) to 10ngmL(-1) with r(2)=0.99 and limits of detection and quantification, respectively of 4pgmL(-1) and 120pgmL(-1) in MilliQ water, were achieved. The method proved to be applicable in different types of waters and show key advantages, such

  6. Solid-solid phase transitions via melting in metals

    Pogatscher, S.; Leutenegger, D.; Schawe, J. E. K.; Uggowitzer, P. J.; Löffler, J. F.


    Observing solid-solid phase transitions in-situ with sufficient temporal and spatial resolution is a great challenge, and is often only possible via computer simulations or in model systems. Recently, a study of polymeric colloidal particles, where the particles mimic atoms, revealed an intermediate liquid state in the transition from one solid to another. While not yet observed there, this finding suggests that such phenomena may also occur in metals and alloys. Here we present experimental evidence for a solid-solid transition via the formation of a metastable liquid in a `real' atomic system. We observe this transition in a bulk glass-forming metallic system in-situ using fast differential scanning calorimetry. We investigate the corresponding transformation kinetics and discuss the underlying thermodynamics. The mechanism is likely to be a feature of many metallic glasses and metals in general, and may provide further insight into phase transition theory.

  7. Direct-immersion solid-phase microextraction coupled to fast gas chromatography mass spectrometry as a purification step for polycyclic aromatic hydrocarbons determination in olive oil.

    Purcaro, Giorgia; Picardo, Massimo; Barp, Laura; Moret, Sabrina; Conte, Lanfranco S


    The aim of the present work was to optimize a preparation step for polycyclic aromatic hydrocarbons in a fatty extract. Solid-phase microextraction is an easy preparation technique, which allows to minimize solvent consumption and reduce sample manipulation. A Carbopack Z/polydimethylsiloxane fiber, particularly suitable for extraction of planar compounds, was employed to extract polycyclic aromatic hydrocarbons from a hexane solution obtained after a previous extraction with acetonitrile from oil, followed by a liquid-liquid partition between acetonitrile and hexane. The proposed method was a rapid and sensitive solution to reduce the interference of triglycerides saving the column life and avoiding frequent cleaning of the mass spectrometer ion source. Despite the non-quantitative extraction of polycyclic aromatic hydrocarbons from oil using acetonitrile, the signal-to-noise ratio was significantly improved obtaining a limit of detection largely below the performance criteria required by the European Union legislation.

  8. Molecular Modeling of Solid Fluid Phase Behavior

    Peter A. Monson


    This report gives a summary of the achievements under DOE contract No. DOE/ER/14150 during the period September 1, 1990 to December 31, 2007. This project was concerned with the molecular modeling of solid-fluid equilibrium. The focus was on understanding how solid-fluid and solid-solid phase behavior are related to molecular structure, and the research program made a seminal contribution in this area. The project led to 34 journal articles, including a comprehensive review article published in Advances in Chemical Physics. The DOE funding supported the work of 5 Ph.D. students, 2 M.S. students and 5 postdoctoral researchers.

  9. Binary Solid-Liquid Phase Equilibria

    Ellison, Herbert R.


    Indicates some of the information that may be obtained from a binary solid-liquid phase equilibria experiment and a method to write a computer program that will plot an ideal phase diagram to which the experimental results may be compared. (Author/CP)

  10. High-throughput assay for quantification of the plasma concentrations of thiopental using automated solid phase extraction (SPE) directly coupled to LC-MS/MS instrumentation.

    Moosavi, Seyed Mojtaba; Shekar, Kiran; Fraser, John; Smith, Maree T; Ghassabian, Sussan


    Most previous assays for thiopental are time-consuming due to laborious sample extraction steps prior to analysis using gas chromatography or high pressure liquid chromatography. Here, we describe the first high-throughput liquid chromatography - tandem mass spectrometry (LC-MS/MS) method for quantification of thiopental concentrations in samples of human plasma. Robotic on-line solid phase extraction (SPE) was used to elute the analytes of interest from samples of human plasma (50μL) loaded onto C18 SPE cartridges to which were added aliquots (50μL) of internal standard solution (thiopental-d5 100ng/mL) and 0.5% formic acid in water (100μL). Cartridges were washed using 10% methanol in ammonium acetate buffer (50mM, pH 7) before elution with mobile phase comprising 0.1% formic acid in water and acetonitrile with a flow rate of 0.55mL/min using a 7.2min run time. The analytes were separated on a C18 XTerra(®) analytical column. Mass spectrometry detection was performed using a QTrap 5500 mass spectrometer (AB Sciex) with negative ionisation. The multiple reaction monitoring (MRM) transitions for thiopental and the internal standard were 241→58, and 246→58, respectively. The calibration curve was linear over a range of 6-600ng/mL. Thiopental was stable in human plasma samples for at least 36h in the autosampler, as well as after three cycles of freeze and thaw, and after 3h storage at room temperature. The absolute recovery and matrix effect were 102% and 6.9%, respectively, and the within-run and between-run precision and accuracy were ≤15%. Our method is fully-validated and satisfies the requirements of the 2012 European Medicines Agency (EMEA) guideline for Bioanalytical Method Validation. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Study of the influence of particles on turbulence with the help of direct and large eddy simulations of gas-solid two-phase flows

    Boivin, M.


    An investigation of dilute dispersed turbulent two-way coupling two-phase flows has been undertaken with the hemp of Direct Numerical Simulations (DNS) on stationary-forced homogeneous isotropic turbulence. The particle relaxation times range from the Kolmogorov to the Eulerian time scales and the load goes up to 1. The analyses is made within the Eulerian-model framework, enhanced by the National Hydraulics Laboratory Lagrangian approach, which is extended here to include inverse coupling and Reynolds effects. Particles are found to dissipate on average turbulence energy. The spectra of the fluid-particle exchange energy rate show that small particles drag the fluid at high wavenumbers, which explains the observed relative increase of small scale energy. A spectral analysis points as responsible mechanism the transfer of fluid-particle covariance by fluid turbulence. Regarding the modeling, he Reynolds dependency and the load contribution are found crucial for good predictions of the dispersed phase moments. A study for practical applications with Large Eddy Simulations (LES) has yielded: LES can be used two-way coupling two-phase flows provided that a dynamic mixed sub-grid scale model is adopted and the particle relaxation time is larger than the cutoff filter one; the inverse coupling should depend more on the position of this relaxation time with respect to the Eulerian one than to the Kolmogorov one. (author) 67 refs.

  12. Direct synthesis of nitrogen-doped graphene on platinum wire as a new fiber coating method for the solid-phase microextraction of BXes in water samples: Comparison of headspace and cold-fiber headspace modes.

    Memarian, Elham; Hosseiny Davarani, Saied Saeed; Nojavan, Saeed; Movahed, Siyavash Kazemi


    In this work, a new solid-phase microextraction fiber was prepared based on nitrogen-doped graphene (N-doped G). Moreover, a new strategy was proposed to solve problems dealt in direct coating of N-doped G. For this purpose, first, Graphene oxide (GO) was coated on Pt wire by electrophoretic deposition method. Then, chemical reduction of coated GO to N-doped G was accomplished by hydrazine and NH3. The prepared fiber showed good mechanical and thermal stabilities. The obtained fiber was used in two different modes (conventional headspace solid-phase microextraction and cold-fiber headspace solid-phase microextraction (CF-HS-SPME)). Both modes were optimized and applied for the extraction of benzene and xylenes from different aqueous samples. All effective parameters including extraction time, salt content, stirring rate, and desorption time were optimized. The optimized CF-HS-SPME combined with GC-FID showed good limit of detections (LODs) (0.3-2.3 μg/L), limit of quantifications (LOQs) (1.0-7.0 μg/L) and linear ranges (1.0-5000 μg/L). The developed method was applied for the analysis of benzene and xylenes in rainwater and some wastewater samples.

  13. Solid-phase extraction with the metal-organic framework MIL-101(Cr) combined with direct analysis in real time mass spectrometry for the fast analysis of triazine herbicides.

    Li, Xianjiang; Xing, Jiawei; Chang, Cuilan; Wang, Xin; Bai, Yu; Yan, Xiuping; Liu, Huwei


    MIL-101(Cr) is an excellent metal-organic framework with high surface area and nanoscale cavities, making it promising in solid-phase extraction. Herein, we used MIL-101(Cr) as a solid-phase extraction packing material combined with fast detection of direct analysis in real time mass spectrometry (DART-MS) for the analysis of triazine herbicides. After systematic optimization of the operation parameters, including the gas temperature of DART, the moving speed of the 1D platform, solvent for desorption, amount of MIL-101(Cr) extraction time, eluent volume and salt concentration, this method can realize the simultaneous detection of five kinds of triazine herbicides. The limits of detection were 0.1∼0.2 ng/mL and the linear ranges covered more than two orders of magnitude with the quantitation limits of 0.5∼1 ng/mL. Moreover, the developed method has been applied for the analysis of lake water samples and the recoveries for spiked analytes were in the range of 85∼110%. These results showed that solid-phase extraction with metal-organic frameworks is an efficient sample preparation approach for DART-MS analysis and could find more applications in environmental analysis.

  14. Direct Zinc Determination in Brazilian Sugar Cane Spirit by Solid-Phase Extraction Using Moringa oleifera Husks in a Flow System with Detection by FAAS

    Vanessa N. Alves


    Full Text Available This paper reports a method for the determination of zinc in Brazilian sugar cane spirit, (cachaça in Portuguese, using solid-phase extraction with a flow injection analysis system and detection by FAAS. The sorbent material used was activated carbon obtained from Moringa oleifera husks. Flow and chemical variables of the proposed system were optimized through multivariate designs. The factors selected were sorbent mass, sample pH, sample flow rate, and eluent concentration. The optimum extraction conditions were obtained using a sample pH of 4.0, a sample flow rate of 6.0 mL min-1, 30.0 mg of sorbent mass, and 1.0 mol L-1 HNO3 as the eluent at a flow rate of 4.0 mL min-1. The limit of detection for zinc was 1.9 μg L-1, and the precision was below 0.82% (20.0 μg L-1, n=7. The analytical curve was linear from 2 to 50 μg L-1, with a correlation coefficient of 0.9996. The method developed was successfully applied to spiked Brazilian sugar cane spirit, and accuracy was assessed through recovery tests, with results ranging from 83% to 100%.

  15. Solid phase sequencing of biopolymers

    Cantor, Charles R.; Hubert, Koster


    This invention relates to methods for detecting and sequencing target nucleic acid sequences, to mass modified nucleic acid probes and arrays of probes useful in these methods, and to kits and systems which contain these probes. Useful methods involve hybridizing the nucleic acids or nucleic acids which represent complementary or homologous sequences of the target to an array of nucleic acid probes. These probes comprise a single-stranded portion, an optional double-stranded portion and a variable sequence within the single-stranded portion. The molecular weights of the hybridized nucleic acids of the set can be determined by mass spectroscopy, and the sequence of the target determined from the molecular weights of the fragments. Probes may be affixed to a solid support such as a hybridization chip to facilitate automated molecular weight analysis and identification of the target sequence.

  16. Solid phase sequencing of biopolymers

    Cantor, Charles (Del Mar, CA); Koster, Hubert (La Jolla, CA)


    This invention relates to methods for detecting and sequencing target nucleic acid sequences, to mass modified nucleic acid probes and arrays of probes useful in these methods, and to kits and systems which contain these probes. Useful methods involve hybridizing the nucleic acids or nucleic acids which represent complementary or homologous sequences of the target to an array of nucleic acid probes. These probes comprise a single-stranded portion, an optional double-stranded portion and a variable sequence within the single-stranded portion. The molecular weights of the hybridized nucleic acids of the set can be determined by mass spectroscopy, and the sequence of the target determined from the molecular weights of the fragments. Nucleic acids whose sequences can be determined include DNA or RNA in biological samples such as patient biopsies and environmental samples. Probes may be fixed to a solid support such as a hybridization chip to facilitate automated molecular weight analysis and identification of the target sequence.

  17. On-site analysis of volatile nitrosamines in food model systems by solid-phase microextraction coupled to a direct extraction device.

    Ventanas, S; Ruiz, J


    Analysis of nitrosamine (NA) standards in a model system was carried out by extraction using SPME coupled to a direct extraction device (DED) and subsequent GC/MS in selected ion monitoring mode. Gelatine (20%, w/v) systems of a NA standard (10mugL(-1)) were prepared, in order to mimic food protein matrix systems such as meat and meat products, fish and so on. Different SPME fibre coatings were tested Both divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) and carboxen/polydimethylsiloxane (CAR/PDMS) fibres coupled to DED satisfactorily extracted all nine NA included in the studied standard (EPA 8270 nitrosamines mix, Sigma-Aldrich) from the gelatine system at 25 degrees C without any sample manipulation. Values of reproducibility, linearity and limit of detection for each type of fibre are reported. SPME-DED appears as a rapid, non-destructive technique for preliminary screening of the presence of toxic substances such as NA in solid foods.

  18. Direct modeling of the electrochemistry in the three-phase boundary of solid oxide fuel cell anodes by density functional theory: a critical overview.

    Shishkin, M; Ziegler, T


    The first principles modeling of electrochemical reactions has proven useful for the development of efficient, durable and low cost solid oxide full cells (SOFCs). In this account we focus on recent advances in modeling of structural, electronic and catalytic properties of the SOFC anodes based on density functional theory (DFT) first principle calculations. As a starting point, we highlight that the adequate analysis of cell electrochemistry generally requires modeling of chemical reactions at the metal/oxide interface rather than on individual metal or oxide surfaces. The atomic models of Ni/YSZ and Ni/CeO2 interfaces, required for DFT simulations of reactions on SOFC anodes are discussed next, together with the analysis of the electronic structure of these interfaces. Then we proceed to DFT-based findings on charge transfer mechanisms during redox reactions on these two anodes. We provide a comparison of the electronic properties of Ni/YSZ and Ni/CeO2 interfaces and present an interpretation of their different chemical performances. Subsequently we discuss the computed energy pathways of fuel oxidation mechanisms, obtained by various groups to date. We also discuss the results of DFT studies combined with microkinetic modeling as well as the results of kinetic Monte Carlo simulations. In conclusion we summarize the key findings of DFT modeling of metal/oxide interfaces to date and highlight possible directions in the future modeling of SOFC anodes.

  19. Measurements of solids concentration and axial solids velocity in gas-solid two-phase flows.

    Nieuwland, J.J.; Meijer, R.; Kuipers, J.A.M.; Swaaij, van W.P.M.


    Several techniques reported in the literature for measuring solids concentration and solids velocity in (dense) gas-solid two-phase flow have been briefly reviewed. An optical measuring system, based on detection of light reflected by the suspended particles, has been developed to measure local soli

  20. Phase 2, Solid waste retrieval strategy

    Johnson, D.M.


    Solid TRU retrieval, Phase 1 is scheduled to commence operation in 1998 at 218W-4C-T01 and complete recovery of the waste containers in 2001. Phase 2 Retrieval will recover the remaining buried TRU waste to be retrieved and provide the preliminary characterization by non-destructive means to allow interim storage until processing for disposal. This document reports on researching the characterization documents to determine the types of wastes to be retrieved and where located, waste configurations, conditions, and required methods for retrieval. Also included are discussions of wastes encompassed by Phase 2 for which there are valid reasons to not retrieve.

  1. Megabar pressure phases of solid hydrogen

    Chen, Nancy Hueling

    The behavior of solid Hsb2, Dsb2, and HD at low temperatures high pressures was investigated. The experimental data were obtained by combining high pressure diamond anvil cell apparatus with cryogenic and spectroscopic techniques. Megabar pressures (1 bar = 10sp5 Pa) and liquid helium temperatures were accessible. The observed phases and phase lines are discussed with respect to orientational order, crystal structure, and electronic properties. The orientational order-disorder phase transition in HD was studied by Raman spectroscopy. Due to the distinguishability of the nuclei in an HD molecule, the observed phase line exhibits surprising behavior relative to that expected for the homonuclear molecules Hsb2 and Dsb2. The megabar pressure phase diagram of solid Dsb2 was investigated by infrared and Raman spectroscopy. The broken symmetry phase (BSP) transition line and the D-A phase line were observed to meet at a triple point. The relative arrangement of phase lines in P-T space, combined with group theoretical analysis of observed infrared and Raman spectra within the phases, sets symmetry restrictions on the allowed crystal structures. The electronic properties of the high pressure H-A and D-A phases were examined, since these recently discovered phases were suspected of being metallic. Acquired broadband infrared absorption spectra extending to 10 mum were analyzed in terms of the Drude model for metals. No evidence indicating metallic behavior was found. Refinements in high pressure techniques were explored, in order to increase the maximum pressures attainable. A method of extending ruby fluorescence pressure measurements to multimegabar pressures was developed, which involved excitation of ruby fluorescence with red, rather than blue or green laser light.

  2. Solid phase synthesis of bifunctional antibodies.

    DeSilva, B S; Wilson, G S


    Bifunctional antibodies were prepared using the principle of solid-phase synthesis. The two Fab' fragments were chemically linked together via a bismaleimide crosslinking reagent. The F(ab')2 fragments from intact IgG were prepared using an immobilized pepsin column. Goat, mouse and human antibodies were digested completely within 4 h. The F(ab')2 fragments thus produced did not contain any IgG impurities. The Fab' fragments were produced by reducing the inter-heavy chain disulfide bonds using 2-mercaptoethylamine. The use of the solid-phase reactor in the preparation of the bifunctional antibodies eliminated many of the time-consuming separation steps between the fragmentation and conjugation steps. This procedure facilitates the automation of the bifunctional antibody preparation and the rapid optimization of reaction conditions.

  3. [Solid phase techniques in blood group serology].

    Uthemann, H; Sturmfels, L; Lenhard, V


    As alternatives to hemagglutination, solid-phase red blood cell adherence assays are of increasing importance. The adaptation of the new techniques to microplates offers several advantages over hemagglutination. Using microplates the assays may be processed semiautomatically, and the results can be read spectrophotometrically and interpreted by a personal computer. In this paper, different red blood cell adherence assays for AB0 grouping, Rh typing, Rh phenotyping, antibody screening and identification, as well as crossmatching will be described.

  4. Recent advances in solid phase peptide synthesis

    White, P.D.


    Since its introduction by Merrifield half a century ago, solid phase peptide synthesis has evolved to become the enabling technology for the development of peptide therapeutics. Using modern methods, 100 - 1000s of peptides can be routinely synthesised in parallel for screening as leads for drug development and peptide APIs are produced in ton scale. In this talk I consider the state of art and report on recent advances to overcome remaining issues such as aspartimide formation, racemisation ...

  5. Development of headspace solid-phase microextraction method for ...

    ... solid-phase microextraction method for the analysis of pesticide residues in fruit and ... Journal of Applied Sciences and Environmental Management ... interface temperature) and solid phase microextraction parameters (fiber coating type, ...

  6. Wax Precipitation Modeled with Many Mixed Solid Phases

    Heidemann, Robert A.; Madsen, Jesper; Stenby, Erling Halfdan


    The behavior of the Coutinho UNIQUAC model for solid wax phases has been examined. The model can produce as many mixed solid phases as the number of waxy components. In binary mixtures, the solid rich in the lighter component contains little of the heavier component but the second phase shows sub...

  7. Parallel solid-phase synthesis of diaryltriazoles

    Matthias Wrobel


    Full Text Available A series of substituted diaryltriazoles was prepared by a solid-phase-synthesis protocol using a modified Wang resin. The copper(I- or ruthenium(II-catalyzed 1,3-cycloaddition on the polymer bead allowed a rapid synthesis of the target compounds in a parallel fashion with in many cases good to excellent yields. Substituted diaryltriazoles resemble a molecular structure similar to established terphenyl-alpha-helix peptide mimics and have therefore the potential to act as selective inhibitors for protein–protein interactions.

  8. Methodical evaluation and improvement of matrix compatible PDMS-overcoated coating for direct immersion solid phase microextraction gas chromatography (DI-SPME-GC)-based applications.

    Souza-Silva, Érica A; Gionfriddo, Emanuela; Shirey, Robert; Sidisky, Len; Pawliszyn, Janusz


    The main quest for the implementation of direct SPME to complex matrices has been the development of matrix compatible coatings that provide sufficient sensitivity towards the target analytes. In this context, we present here a thorough evaluation of PDMS-overcoated fibers suitable for simultaneous extraction of different polarities analytes, while maintaining adequate matrix compatibility. For this, eleven analytes were selected, from various application classes (pesticides, industrial chemicals and pharmaceuticals) and with a wide range of log P values (ranging from 1.43 to 6). The model matrix chosen was commercial Concord grape juice, which is rich in pigments such as anthocyanins, and contains approximately 20% of sugar (w/w). Two types of PDMS, as well as other intrinsic factors associated with the PDMS-overcoated fiber fabrication are studied. The evaluation showed that the PDMS-overcoated fibers considerably slowed down the coating fouling process during direct immersion in complex matrices of high sugar content. Longevity differences could be seen between the two types of PDMS tested, with a proprietary Sylgard(®) giving superior performance because of lesser amount of reactive groups and enhanced hydrophobicity. Conversely, the thickness of the outer layer did not seem to have a significant effect on the fiber lifetime. We also demonstrate that the uniformity of the overcoated PDMS layer is paramount to the achievement of reliable data and extended fiber lifetime. Employing the optimum overcoated fiber, limits of detection (LOD) in the range of 0.2-1.3 ng/g could be achieved. Additional improvement is attainable by introducing washing of the coatings after desorption, so that any carbon build-up (fouling) left on the coating surface after thermal desorption can be removed.

  9. Detection of oligonucleotide hybridization on a single microparticle by time-resolved fluorometry: hybridization assays on polymer particles obtained by direct solid phase assembly of the oligonucleotide probes.

    Hakala, H; Heinonen, P; Iitiä, A; Lönnberg, H


    Oligodeoxyribonucleotides were assembled by conventional phosphoramidite chemistry on uniformly sized (50 microns) porous glycidyl methacrylate/ethylene dimethacrylate (SINTEF) and compact polystyrene (Dynosphere) particles, the aminoalkyl side chains of which were further derivatized with DMTrO-acetyl groups. The linker was completely resistant toward ammonolytic deprotection of the base moieties. The quality of oligonucleotides was assessed by repeating the synthesis on the same particles derivatized with a cleavable ester linker. The ability of the oligonucleotide-coated particles to bind complementary sequences via hybridization was examined by following the attachment of oligonucleotides bearing a photoluminescent europium(III) chelate to the particles. The fluorescence emission was measured directly on a single particle. The effects of the following factors on the kinetics and efficiency of hybridization were studied: number of particles in a given volume of the assay solution, loading of oligonucleotide on the particle, concentration of the target oligonucleotide in solution, length of the hybridizing sequence, presence of noncomplementary sequences, and ionic strength. The fluorescence signal measured on a single particle after hybridization was observed to be proportional to the concentration of the target oligonucleotide in solution over a concentration range of 5 orders of magnitude.

  10. Oscillatory burning of solid propellants including gas phase time lag.

    T'Ien, J. S.


    An analysis has been performed for oscillatory burning of solid propellants including gas phase time lag. The gaseous flame is assumed to be premixed and laminar with a one-step overall chemical reaction. The propellant is assumed to decompose according to the Arrenhius Law, with no condensed phase reaction. With this model, strong gas phase resonance has been found in certain cases at the characteristic gas-phase frequencies, but the peaking of the acoustic admittance is in the direction favoring the damping of pressure waves. At still higher frequencies, moderate wave-amplifying ability was found. The limit of low frequency response obtained previously by Denison and Baum was recovered, and the limitations of the quasi-steady theory were investigated.

  11. Oscillatory burning of solid propellants including gas phase time lag.

    T'Ien, J. S.


    An analysis has been performed for oscillatory burning of solid propellants including gas phase time lag. The gaseous flame is assumed to be premixed and laminar with a one-step overall chemical reaction. The propellant is assumed to decompose according to the Arrenhius Law, with no condensed phase reaction. With this model, strong gas phase resonance has been found in certain cases at the characteristic gas-phase frequencies, but the peaking of the acoustic admittance is in the direction favoring the damping of pressure waves. At still higher frequencies, moderate wave-amplifying ability was found. The limit of low frequency response obtained previously by Denison and Baum was recovered, and the limitations of the quasi-steady theory were investigated.

  12. Solid phase microextraction device using aerogel

    Miller, Fred S.; Andresen, Brian D.


    A sample collection substrate of aerogel and/or xerogel materials bound to a support structure is used as a solid phase microextraction (SPME) device. The xerogels and aerogels may be organic or inorganic and doped with metals or other compounds to target specific chemical analytes. The support structure is typically formed of a glass fiber or a metal wire (stainless steel or kovar). The devices are made by applying gel solution to the support structures and drying the solution to form aerogel or xerogel. Aerogel particles may be attached to the wet layer before drying to increase sample collection surface area. These devices are robust, stable in fields of high radiation, and highly effective at collecting gas and liquid samples while maintaining superior mechanical and thermal stability during routine use. Aerogel SPME devices are advantageous for use in GC/MS analyses due to their lack of interfering background and tolerance of GC thermal cycling.

  13. Sol-gel hybrid methyltrimethoxysilane-tetraethoxysilane as a new dispersive solid-phase extraction material for acrylamide determination in food with direct gas chromatography-mass spectrometry analysis.

    Omar, Mei Musa Ali; Wan Ibrahim, Wan Aini; Elbashir, Abdalla Ahmed


    A sol-gel hybrid sorbent, methyltrimethoxysilane-tetraethoxysilane (MTMOS-TEOS) was successfully used as new dispersive solid phase extraction (dSPE) sorbent material in the determination of acrylamide in several Sudanese foods and analysis using GC-MS. Several important dSPE parameters were optimised. Under the optimised conditions, excellent linearity (r(2)>0.9998) was achieved using matrix matched standard calibration in the concentration range 50-1000 μg kg(-1). The limits of detection (LOD) and limit of quantification ranged from 9.1 to 12.8 μg/kg and 27.8-38.9 μg/kg, respectively. The precision (RSD%) of the method was ⩽6.6% and recoveries of acrylamide obtained were in the range of 88-103%, (n=3). The LOD obtained is comparable with the LODs of primary secondary amine dSPE. The proposed MTMOS-TEOS dSPE method is direct and safe for acrylamide analysis, showed reliable method validation performances and good cleanup effects. It was successfully applied to the analysis of acrylamide in real food samples.

  14. Direct analysis of 18 flavonol glycosides, aglycones and terpene trilactones in Ginkgo biloba tablets by matrix solid phase dispersion coupled with ultra-high performance liquid chromatography tandem triple quadrupole mass spectrometry.

    Liu, Xin-Guang; Yang, Hua; Cheng, Xiao-Lan; Liu, Lei; Qin, Yong; Wang, Qi; Qi, Lian-Wen; Li, Ping


    Analysis and quality control of Ginkgo biloba have been comprehensively studied. However, little attention has been devoted to the simultaneous extraction and analysis of flavonols and terpene trilactones, especially for direct quantification of flavonol glycosides. This work described a rapid strategy for one-step extraction and quantification of the components. A matrix solid phase dispersion (MSPD) method was designed for the extraction of ginkgo ingredients and compared with the heat-reflux and ultrasonic extraction methods. An ultra-high performance liquid chromatography (UHPLC)-tandem-triple-quadrupole-mass spectrometry (QQQ-MS) method was developed for detection of the 18 components, including 10 original flavonol glycosides, 3 aglycones, and 5 lactones. Subsequently, the proposed strategy was used for the analysis of 12 G. biloba tablets. Results showed that MSPD produced comparable extraction efficiency but consumed less time and required lower solvent volumes compared with conventional methods. Without hydrolysis, the concentration detected was much closer to the original in the sample. The total flavonol glycoside contents in ginkgo tablets ranged from 3.59 to 125.21μgmg(-1), and the terpene trilactone varied from 3.45 to 57.8μgmg(-1) among different manufacturers. In conclusion, the proposed MSPD and UHPLC-QQQ-MS is rapid and sensitive in providing comprehensive profile of chemical constituents especially the genuine flavonol glycosides for improved quality control of ginkgo products.

  15. Solid Phase Synthesis of Polymacromer and Copolymacromer Brushes


    REPORT Solid Phase Synthesis of Polymacromer and Copolymacromer Brushes 14. ABSTRACT 16. SECURITY CLASSIFICATION OF: We report a novel solid phase...form poly-macromer brushes wherein macromonomers are linked via triazole groups. After each addition step, the terminal alkyne group can be deprotected...Research Triangle Park, NC 27709-2211 15. SUBJECT TERMS Solid Phase Synthesis , polymers and copolymers Hernán R. Rengifo, Cristian Grigoras, Benjamin I

  16. Novel materials and methods for solid-phase extraction and liquid chromatography

    Ambrose, Diana [Iowa State Univ., Ames, IA (United States)


    This report contains a general introduction which discusses solid-phase extraction and solid-phase micro-extraction as sample preparation techniques for high-performance liquid chromatography, which is also evaluated in the study. This report also contains the Conclusions section. Four sections have been removed and processed separately: silicalite as a sorbent for solid-phase extraction; a new, high-capacity carboxylic acid functionalized resin for solid-phase extraction; semi-micro solid-phase extraction of organic compounds from aqueous and biological samples; and the high-performance liquid chromatographic determination of drugs and metabolites in human serum and urine using direct injection and a unique molecular sieve.

  17. A directly phase-modulated light source

    Yuan, Z L; Lucamarini, M; Roberts, G L; Dynes, J F; Shields, A J


    The art of imparting information onto a light wave by optical signal modulation is fundamental to all forms of optical communication. Among many schemes, direct modulation of laser diodes stands out as a simple, robust, and cost effective method. However, the simultaneous changes in intensity, frequency and phase are a drawback which has prevented its application in the field of secure quantum communication. Here, we propose and experimentally demonstrate a directly phase-modulated light source which overcomes the main disadvantages associated with direct modulation and is suitable for diverse applications such as coherent communications and quantum cryptography. The source separates the tasks of phase preparation and pulse generation between a pair of semiconductor lasers leading to very pure phase states. Moreover, the cavity enhanced electro-optic effect enables the first example of sub-volt halfwave phase modulation at high signal rates. The source is compact, stable and versatile, and we show its potenti...

  18. Stable solid-phase Rh antigen.

    Yared, M A; Moise, K J; Rodkey, L S


    Numerous investigators have attempted to isolate the Rh antigens in a stable, immunologically reactive form since the discovery of the Rh system over 56 years ago. We report here a successful and reproducible approach to solubilizing and adsorbing the human Rh antigen(s) to a solid-phase matrix in an antigenically active form. Similar results were obtained with rabbit A/D/F red blood cell antigens. The antigen preparation was made by dissolution of the red blood cell membrane lipid followed by fragmentation of the residual cytoskeleton in an EDTA solution at low ionic strength. The antigenic activity of the soluble preparations was labile in standard buffers but was stable in zwitterionic buffers for extended periods of time. Further studies showed that the antigenic activity of these preparations was enhanced, as was their affinity for plastic surfaces, in the presence of acidic zwitterionic buffers. Adherence to plastic surfaces at low pH maintained antigenic reactivity and specificity for antibody was retained. The data show that this approach yields a stable form of antigenically active human Rh D antigen that could be used in a red blood cell-free assay for quantitative analysis of Rh D antibody and for Rh D antibody immunoadsorption and purification.

  19. RF waveguide phase-directed power combiners

    Nantista, Christopher D.; Dolgashev, Valery A.; Tantawi, Sami G.


    High power RF phase-directed power combiners include magic H hybrid and/or superhybrid circuits oriented in orthogonal H-planes and connected using E-plane bends and/or twists to produce compact 3D waveguide circuits, including 8.times.8 and 16.times.16 combiners. Using phase control at the input ports, RF power can be directed to a single output port, enabling fast switching between output ports for applications such as multi-angle radiation therapy.

  20. Preparation of Ion Exchange Films for Solid-Phase Spectrophotometry and Solid-Phase Fluorometry

    Hill, Carol M.; Street, Kenneth W.; Tanner, Stephen P.; Philipp, Warren H.


    Atomic spectroscopy has dominated the field of trace inorganic analysis because of its high sensitivity and selectivity. The advantages gained by the atomic spectroscopies come with the disadvantage of expensive and often complicated instrumentation. Solid-phase spectroscopy, in which the analyte is preconcentrated on a solid medium followed by conventional spectrophotometry or fluorometry, requires less expensive instrumentation and has considerable sensitivity and selectivity. The sensitivity gains come from preconcentration and the use of chromophore (or fluorophore) developers and the selectivity is achieved by use of ion exchange conditions that favor the analyte in combination with speciative chromophores. Little work has been done to optimize the ion exchange medium (IEM) associated with these techniques. In this report we present a method for making ion exchange polymer films, which considerably simplify the solid-phase spectroscopic techniques. The polymer consists of formaldehyde-crosslinked polyvinyl alcohol with polyacrylic acid entrapped therein. The films are a carboxylate weak cation exchanger in the calcium form. They are mechanically sturdy and optically transparent in the ultraviolet and visible portion of the spectrum, which makes them suitable for spectrophotometry and fluorometry.

  1. Investigation of binary solid phases by calorimetry and kinetic modelling

    Matovic, M.


    The traditional methods for the determination of liquid-solid phase diagrams are based on the assumption that the overall equilibrium is established between the phases. However, the result of the crystallization of a liquid mixture will typically be a non-equilibrium or metastable state of the solid

  2. Utilization of highly robust and selective crosslinked polymeric ionic liquid-based sorbent coatings in direct-immersion solid-phase microextraction and high-performance liquid chromatography for determining polar organic pollutants in waters.

    Pacheco-Fernández, Idaira; Najafi, Ali; Pino, Verónica; Anderson, Jared L; Ayala, Juan H; Afonso, Ana M


    Several crosslinked polymeric ionic liquid (PIL)-based sorbent coatings of different nature were prepared by UV polymerization onto nitinol wires. They were evaluated in a direct-immersion solid-phase microextraction (DI-SPME) method in combination with high-performance liquid chromatography (HPLC) and diode array detection (DAD). The studied PIL coatings contained either vinyl alkyl or vinylbenzyl imidazolium-based (ViCnIm- or ViBCnIm-) IL monomers with different anions, as well as different dicationic IL crosslinkers. The analytical performance of these PIL-based SPME coatings was firstly evaluated for the extraction of a group of 10 different model analytes, including hydrocarbons and phenols, while exhaustively comparing the performance with commercial SPME fibers such as polydimethylsyloxane (PDMS), polyacrylate (PA) and polydimethylsiloxane/divinylbenzene (PDMS/DVB), and using all fibers under optimized conditions. Those fibers exhibiting a high selectivity for polar compounds were selected to carry out an analytical method for a group of 5 alkylphenols, including bisphenol-A (BPA) and nonylphenol (n-NP). Under optimum conditions, average relative recoveries of 108% and inter-day precision values (3 non-consecutive days) lower than 19% were obtained for a spiked level of 10µgL(-1). Correlations coefficients for the overall method ranged between 0.990 and 0.999, and limits of detection were down to 1µgL(-1). Tap water, river water, and bottled water were analyzed to evaluate matrix effects. Comparison with the PA fiber was also performed in terms of analytical performance. Partition coefficients (logKfs) of the alkylphenols to the SPME coating varied from 1.69 to 2.45 for the most efficient PIL-based fiber, and from 1.58 to 2.30 for the PA fiber. These results agree with those obtained by the normalized calibration slopes, pointing out the affinity of these PILs-based coatings.

  3. Proton sponge-functionalized silica as high performance adsorbents for solid-phase extraction of trace perfluoroalkyl sulfonates in the environmental water samples and their direct analysis by MALDI-TOF-MS.

    Cao, Dong; Hu, Ming; Han, Chunguang; Yu, Jiyao; Cui, Lin; Liu, Yongxue; Wang, Hailin; Cai, Yaqi; Kang, Yuehui; Zhou, Yiqi


    1,8-Bis(dimethylamino)naphthalene (DMAN), a classical 'proton sponge', was functionalized on silica particles as a novel solid-phase extraction (SPE) adsorbent (DMAN@silica) for extracting perfluoroalkyl sulfonates (PFSs). High reproducibility and excellent extraction capability for PFSs were obtained in a wide pH range (3.0~8.5). The adsorbed PFSs on DMAN@silica sorbents could be efficiently eluted by 1,8-bis(tetramethylguanidino)naphthalene (TMGN) solution which is a proton sponge with higher proton affinity than DMAN. The elution could be directly analyzed by MALDI-TOF-MS using TMGN as matrix. Clear mass spectra for the PFSs were obtained due to no matrix ions interference observed. Furthermore, a novel strategy based on the DMAN@silica-SPE enrichment, followed by MALDI-TOF-MS analysis, was proposed and applied for PFSs quantification in environmental water samples. The calibration curves of each of the target analytes showed a wide linear dynamic range of response (0.1-10 ng L(-1) for perfluorooctane sulfonate (PFOS), perfluorohexyl sulfonate (PFHxS) and perfluorobutylsulfonate (PFBS)), which were over 2 orders of magnitude. The detection limits for PFOS, PFHxS, and PFBS were 0.021, 0.016, and 0.013 ng L(-1), respectively (S/N = 3). Recoveries of PFOS, PFHxS, and PFBS are in the ranges of 92-104%, 95-102%, and 98-109% for spiked river water samples. These results indicated that the prepared DMAN@silica adsorbents could efficiently enrich PFSs and that the proposed method is reliable.

  4. Proposed method for controlling turbid particles in solid-phase bioluminescent toxicity measurement.

    Yeo, Seul-Ki; Park, Jun-Boum; Ahn, Joo-Sung; Han, Young-Soo


    In the recent half century, numerous methods have been developed to assess ecological toxicity. However, the presence of solid-particle turbidity sometimes causes such tests to end with questionable results. Many researchers focused on controlling this arbitrary turbidity effect when using the Microtox® solid-phase toxicity system, but there is not yet a standard method. In this study, we examined four solid-phase sample test methods recommended in the Microtox® manual, or proposed from the literature, and compared the existing methods with our proposed method (centrifuged basic solid-phase test, c-BSPT). Four existing methods use the following strategies to control turbid particles: complete separation of liquid and solid using 0.45-μm filtration before contacting solid samples and bacteria, natural settlement, moderate separation of large particles using coarser pore size filtration, and exclusion of light loss in the toxicity calculation caused by turbidity after full disturbance of samples. Our proposed method uses moderate centrifugation to separate out the heavier soil particles from the lighter bacteria after direct contact between them. Among the solid-phase methods tested, in which the bacteria and solid particles were in direct contact (i.e., the three existing methods and the newly proposed one, c-BSPT), no single method could be recommended as optimal for samples over a range of turbidity. Instead, a simple screening strategy for selecting a sample-dependent solid-phase test method was suggested, depending on the turbidity of the solid suspension. The results of this study highlight the importance of considering solid particles, and the necessity for optimal selection of test method to reduce errors in the measurement of solid-phase toxicity.

  5. Solid-solid phase transitions determined by differential scanning calorimetry.

    Murrill, E.; Whitehead, M. E.; Breed, L.


    Data are presented to show that tris(hydroxymethyl)acetic acid, monochloropentaerythritol, monofluoropentaerythritol, difluoropentaerythritol, monoaminopentaerythritol, and diaminopentaerythritol exhibit solid-state transitions to a plastic crystalline state. Transitional enthalpies in many of these substances are lower than might be expected by analogy with related structures, suggesting that some configurational contributions to their entropy increments have been inhibited.

  6. Solid-solid phase transitions determined by differential scanning calorimetry.

    Murrill, E.; Whitehead, M. E.; Breed, L.


    Data are presented to show that tris(hydroxymethyl)acetic acid, monochloropentaerythritol, monofluoropentaerythritol, difluoropentaerythritol, monoaminopentaerythritol, and diaminopentaerythritol exhibit solid-state transitions to a plastic crystalline state. Transitional enthalpies in many of these substances are lower than might be expected by analogy with related structures, suggesting that some configurational contributions to their entropy increments have been inhibited.

  7. Analysis of solid-liquid phase change heat transfer enhancement

    张寅平; 王馨


    Solid-liquid phase change processes have two important features: the process is an approximately isothermal process and the heat of fusion of phase change material tends to be much greater than its specific heat. Therefore, if any phase change material adjacent to a hot or cold surface undergoes phase change, the heat transfer rate on the surface will be noticeably enhanced. This paper presents a novel insight into the mechanisms of heat transfer enhancement induced by solid-liquid phase change based on the analogy analysis for heat conduction with an internal heat source and solid-liquid phase change heat transfer. Three degrees of surface heat transfer enhancement for different conditions are explored, and corresponding formulae are written to describe them. The factors influencing the degrees of heat transfer enhancement are clarified and their effects quantitatively analyzed. Both the novel insight and the analysis contribute to effective application of phase change heat transfer enhancement technique.

  8. Directly Phase-Modulated Light Source

    Yuan, Z. L.; Fröhlich, B.; Lucamarini, M.; Roberts, G. L.; Dynes, J. F.; Shields, A. J.


    The art of imparting information onto a light wave by optical signal modulation is fundamental to all forms of optical communication. Among many schemes, direct modulation of laser diodes stands out as a simple, robust, and cost-effective method. However, the simultaneous changes in intensity, frequency, and phase have prevented its application in the field of secure quantum communication. Here, we propose and experimentally demonstrate a directly phase-modulated light source which overcomes the main disadvantages associated with direct modulation and is suitable for diverse applications such as coherent communications and quantum cryptography. The source separates the tasks of phase preparation and pulse generation between a pair of semiconductor lasers leading to very pure phase states. Moreover, the cavity-enhanced electro-optic effect enables the first example of subvolt half-wave phase modulation at high signal rates. The source is compact, stable, and versatile, and we show its potential to become the standard transmitter for future quantum communication networks based on attenuated laser pulses.

  9. Automated solid-phase synthesis of oligosaccharides containing sialic acids

    Chian-Hui Lai


    Full Text Available A sialic acid glycosyl phosphate building block was designed and synthesized. This building block was used to prepare α-sialylated oligosaccharides by automated solid-phase synthesis selectively.


    B. S. Chandravanshi

    cation exchange-solid phase extraction (SCX-SPE) was investigated as an .... Stock solutions, with a concentration of 1.00 mg/mL were prepared ... Johannesburg, South Africa) connected to a vacuum pump (Vacuubrand, GMBH, Germany).

  11. Solid phase epitaxial regrowth of (001) anatase titanium dioxide

    Barlaz, David Eitan; Seebauer, Edmund G., E-mail: [Department of Chemical and Biomolecular Engineering, University of Illinois, 600 S Mathews Ave., Urbana, Illinois 61801 (United States)


    The growing interest in metal oxide based semiconductor technologies has driven the need to produce high quality epitaxial films of one metal oxide upon another. Largely unrecognized in synthetic efforts is that some metal oxides offer strongly polar surfaces and interfaces that require electrostatic stabilization to avoid a physically implausible divergence in the potential. The present work examines these issues for epitaxial growth of anatase TiO{sub 2} on strontium titanate (001). Solid phase epitaxial regrowth yields only the (001) facet, while direct crystalline growth by atomic layer deposition yields both the (112) and (001). The presence of amorphous TiO{sub 2} during regrowth may provide preferential stabilization for formation of the (001) facet.

  12. Advanced Manufacturing of Intermediate Temperature, Direct Methane Oxidation Membrane Electrode Assemblies for Durable Solid Oxide Fuel Cell Project

    National Aeronautics and Space Administration — The proposed innovation builds on the successes of the Phase I program by integrating our direct oxidation membrane electrode assembly (MEA) into a monolithic solid...

  13. Combinatorial Solid-Phase Synthesis of Balanol Analogues

    Nielsen, John; Lyngsø, Lars Ole


    The natural product balanol has served as a template for the design and synthesis of a combinatorial library using solid-phase chemistry. Using a retrosynthetic analysis, the structural analogues have been assembled from three relatively accessible building blocks. The solid-phase chemistry inclu...... including MSNT-mediated esterification of both support-bound alcohols and carboxylic acids has been implemented successfully. Copyright (C) 1996 Elsevier Science Ltd....

  14. Combinatorial Solid-Phase Synthesis of Balanol Analogues

    Nielsen, John; Lyngsø, Lars Ole


    The natural product balanol has served as a template for the design and synthesis of a combinatorial library using solid-phase chemistry. Using a retrosynthetic analysis, the structural analogues have been assembled from three relatively accessible building blocks. The solid-phase chemistry inclu...... including MSNT-mediated esterification of both support-bound alcohols and carboxylic acids has been implemented successfully. Copyright (C) 1996 Elsevier Science Ltd....

  15. The Structural Phase Transition in Solid DCN

    Dietrich, O. W.; Mackenzie, Gordon A.; Pawley, G. S.


    Neutron scattering measurements on deuterated hydrogen cyanide have shown that the structural phase change from a tetragonal to an orthorhombic form at 160K is a first-order transition. A transverse acoustic phonon mode, which has the symmetry of the phase change, was observed at very low energies...... and showed 'softening' as the transition temperature was approached from above....

  16. Magnetic Solid Phase Extraction Applied to Food Analysis

    Israel S. Ibarra


    Full Text Available Magnetic solid phase extraction has been used as pretreatment technique for the analysis of several compounds because of its advantages when it is compared with classic methods. This methodology is based on the use of magnetic solids as adsorbents for preconcentration of different analytes from complex matrices. Magnetic solid phase extraction minimizes the use of additional steps such as precipitation, centrifugation, and filtration which decreases the manipulation of the sample. In this review, we describe the main procedures used for synthesis, characterization, and application of this pretreatment technique which were applied in food analysis.

  17. Fuel spill identification using solid-phase extraction and solid-phase microextraction. 1. Aviation turbine fuels.

    Lavine, B K; Brzozowski, D M; Ritter, J; Moores, A J; Mayfield, H T


    The water-soluble fraction of aviation jet fuels is examined using solid-phase extraction and solid-phase microextraction. Gas chromatographic profiles of solid-phase extracts and solid-phase microextracts of the water-soluble fraction of kerosene- and nonkerosene-based jet fuels reveal that each jet fuel possesses a unique profile. Pattern recognition analysis reveals fingerprint patterns within the data characteristic of fuel type. By using a novel genetic algorithm (GA) that emulates human pattern recognition through machine learning, it is possible to identify features characteristic of the chromatographic profile of each fuel class. The pattern recognition GA identifies a set of features that optimize the separation of the fuel classes in a plot of the two largest principal components of the data. Because principal components maximize variance, the bulk of the information encoded by the selected features is primarily about the differences between the fuel classes.

  18. Direct Coal Oxidation in Modified Solid Oxide Fuel Cells

    Deleebeeck, Lisa; Gil, Vanesa; Ippolito, Davide


    Hybrid direct carbon fuel cells employ a classical solid oxide fuel cell together with carbon dispersed in a carbonate melt on the anode side. In a European project, the utilization of various coals has been investigated with and without addition of an oxidation catalyst to the carbon-carbonate s......Hybrid direct carbon fuel cells employ a classical solid oxide fuel cell together with carbon dispersed in a carbonate melt on the anode side. In a European project, the utilization of various coals has been investigated with and without addition of an oxidation catalyst to the carbon...

  19. Solidification microstructures and solid-state parallels: Recent developments, future directions

    Asta, M. [Department of Chemical Engineering and Materials Science, University of California at Davis, Davis, CA 95616 (United States); Beckermann, C. [Department of Mechanical and Industrial Engineering, University of Iowa, Iowa City, IA 52242 (United States); Karma, A. [Department of Physics and Center for Interdisciplinary Research on Complex Systems, Northeastern University, Boston, MA 02115 (United States); Kurz, W. [Institute of Materials, Ecole Polytechnique Federale de Lausanne (EPFL), 1015 Lausanne (Switzerland)], E-mail:; Napolitano, R. [Department of Materials Science and Engineering, Iowa State University, and Ames Laboratory USDOE, Ames, IA 50011 (United States); Plapp, M. [Physique de la Matiere Condensee, Ecole Polytechnique, CNRS, 91128 Palaiseau (France); Purdy, G. [Department of Materials Science and Engineering, McMaster University, Hamilton, Ont., L8S 4L7 (Canada); Rappaz, M. [Institute of Materials, Ecole Polytechnique Federale de Lausanne (EPFL), 1015 Lausanne (Switzerland); Trivedi, R. [Department of Materials Science and Engineering, Iowa State University, and Ames Laboratory USDOE, Ames, IA 50011 (United States)


    Rapid advances in atomistic and phase-field modeling techniques as well as new experiments have led to major progress in solidification science during the first years of this century. Here we review the most important findings in this technologically important area that impact our quantitative understanding of: (i) key anisotropic properties of the solid-liquid interface that govern solidification pattern evolution, including the solid-liquid interface free energy and the kinetic coefficient; (ii) dendritic solidification at small and large growth rates, with particular emphasis on orientation selection; (iii) regular and irregular eutectic and peritectic microstructures; (iv) effects of convection on microstructure formation; (v) solidification at a high volume fraction of solid and the related formation of pores and hot cracks; and (vi) solid-state transformations as far as they relate to solidification models and techniques. In light of this progress, critical issues that point to directions for future research in both solidification and solid-state transformations are identified.

  20. Two-dimensional solid-phase extraction strategy for the selective enrichment of aminoglycosides in milk.

    Shen, Aijin; Wei, Jie; Yan, Jingyu; Jin, Gaowa; Ding, Junjie; Yang, Bingcheng; Guo, Zhimou; Zhang, Feifang; Liang, Xinmiao


    An orthogonal two-dimensional solid-phase extraction strategy was established for the selective enrichment of three aminoglycosides including spectinomycin, streptomycin, and dihydrostreptomycin in milk. A reversed-phase liquid chromatography material (C18 ) and a weak cation-exchange material (TGA) were integrated in a single solid-phase extraction cartridge. The feasibility of two-dimensional clean-up procedure that experienced two-step adsorption, two-step rinsing, and two-step elution was systematically investigated. Based on the orthogonality of reversed-phase and weak cation-exchange procedures, the two-dimensional solid-phase extraction strategy could minimize the interference from the hydrophobic matrix existing in traditional reversed-phase solid-phase extraction. In addition, high ionic strength in the extracts could be effectively removed before the second dimension of weak cation-exchange solid-phase extraction. Combined with liquid chromatography and tandem mass spectrometry, the optimized procedure was validated according to the European Union Commission directive 2002/657/EC. A good performance was achieved in terms of linearity, recovery, precision, decision limit, and detection capability in milk. Finally, the optimized two-dimensional clean-up procedure incorporated with liquid chromatography and tandem mass spectrometry was successfully applied to the rapid monitoring of aminoglycoside residues in milk. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. N-Acyliminium Intermediates in Solid-Phase Synthesis

    Quement, Sebastian Thordal le; Petersen, Rico; Meldal, M.


    N-Acyliminium ions are powerful intermediates in synthetic organic chemistry. Examples of their use are numerous in solution-phase synthesis, but there are unmerited few reports on these highly reactive electrophiles in solid-phase synthesis. The present review covers the literature to date and i...

  2. Solid phase extraction method for determination of mitragynine in ...

    mitragynine in urine and its application to mitragynine excretion ... Purpose: To develop a solid phase extraction (SPE) method that utilizes reverse-phase high performance .... solution of MG (1 mg/mL) which was further ... Facility, Prince of Songkla University and carried ..... d), which permit unrestricted use, distribution,.

  3. Heterogeneous Ferroelectric Solid Solutions Phases and Domain States

    Topolov, Vitaly


    The book deals with perovskite-type ferroelectric solid solutions for modern materials science and applications, solving problems of complicated heterophase/domain structures near the morphotropic phase boundary and applications to various systems with morphotropic phases. In this book domain state–interface diagrams are presented for the interpretation of heterophase states in perovskite-type ferroelectric solid solutions. It allows to describe the stress relief in the presence of polydomain phases, the behavior of unit-cell parameters of coexisting phases and the effect of external electric fields. The novelty of the book consists in (i) the first systematization of data about heterophase states and their evolution in ferroelectric solid solutions (ii) the general interpretation of heterophase and domain structures at changing temperature, composition or electric field (iii) the complete analysis of interconnection domain structures, unit-cell parameters changes, heterophase structures and stress relief.

  4. Direct Coal Oxidation in Modified Solid Oxide Fuel Cells

    Deleebeeck, Lisa; Gil, Vanesa; Ippolito, Davide;


    Hybrid direct carbon fuel cells employ a classical solid oxide fuel cell together with carbon dispersed in a carbonate melt on the anode side. In a European project, the utilization of various coals has been investigated with and without addition of an oxidation catalyst to the carbon-carbonate s...

  5. Anisotropic kinetics of solid phase transition from first principles: alpha-omega phase transformation of Zr.

    Guan, Shu-Hui; Liu, Zhi-Pan


    Structural inhomogeneity is ubiquitous in solid crystals and plays critical roles in phase nucleation and propagation. Here, we develop a heterogeneous solid-solid phase transition theory for predicting the prevailing heterophase junctions, the metastable states governing microstructure evolution in solids. Using this theory and first-principles pathway sampling simulation, we determine two types of heterophase junctions pertaining to metal α-ω phase transition at different pressures and predict the reversibility of transformation only at low pressures, i.e. below 7 GPa. The low-pressure transformation is dominated by displacive Martensitic mechanism, while the high-pressure one is controlled by the reconstructive mechanism. The mechanism of α-ω phase transition is thus highly pressure-sensitive, for which the traditional homogeneous model fails to explain the experimental observations. The results provide the first atomic-level evidence on the coexistence of two different solid phase transition mechanisms in one system.

  6. The Structural Phase Transition in Solid DCN

    Dietrich, O. W.; Mackenzie, Gordon A.; Pawley, G. S.


    Neutron scattering measurements on deuterated hydrogen cyanide have shown that the structural phase transition from a tetragonal to an orthorhombic form at 160 K is a first order transition. A transverse acoustic phonon mode, which has the symmetry of the transition was observed at very low energ...... energies and showed “softening” as the transition was approached from above.......Neutron scattering measurements on deuterated hydrogen cyanide have shown that the structural phase transition from a tetragonal to an orthorhombic form at 160 K is a first order transition. A transverse acoustic phonon mode, which has the symmetry of the transition was observed at very low...

  7. Solid Phase Formylation of N-Terminus Peptides

    Anna Lucia Tornesello


    Full Text Available Formylation of amino groups is a critical reaction involved in several biological processes including post-translational modification of histones. The addition of a formyl group (CHO to the N-terminal end of a peptide chain generates biologically active molecules. N-formyl-peptides can be produced by different methods. We performed the N-formylation of two chemotactic hexapetides, Met1-Leu2-Lys3-Leu4-Ile5-Val6 and Met1-Met2-Tyr3-Ala4-Leu5-Phe6, carrying out the reaction directly on peptidyl-resin following pre-activation of formic acid with N,N-dicyclohexylcarbodiimmide (DCC in liquid phase. The overnight incubation at 4 °C resulted in a significant increase in production yields of formylated peptides compared to the reaction performed at room temperature. The method is consistently effective, rapid, and inexpensive. Moreover, the synthetic strategy can be applied for the formylation of all primary amines at N-terminus of peptide chains or amino groups of lysine side-chains in solid phase.

  8. Phase coexistence in ferroelectric solid solutions: Formation of monoclinic phase with enhanced piezoelectricity

    Xiaoyan Lu


    Full Text Available Phase morphology and corresponding piezoelectricity in ferroelectric solid solutions were studied by using a phenomenological theory with the consideration of phase coexistence. Results have shown that phases with similar energy potentials can coexist, thus induce interfacial stresses which lead to the formation of adaptive monoclinic phases. A new tetragonal-like monoclinic to rhombohedral-like monoclinic phase transition was predicted in a shear stress state. Enhanced piezoelectricity can be achieved by manipulating the stress state close to a critical stress field. Phase coexistence is universal in ferroelectric solid solutions and may provide a way to optimize ultra-fine structures and proper stress states to achieve ultrahigh piezoelectricity.

  9. Structural control of Fe-based alloys through diffusional solid/solid phase transformations in a high magnetic field.

    Ohtsuka, Hideyuki


    A magnetic field has a remarkable influence on solid/solid phase transformations and it can be used to control the structure and function of materials during phase transformations. The effects of magnetic fields on diffusional solid/solid phase transformations, mainly from austenite to ferrite, in Fe-based alloys are reviewed. The effects of magnetic fields on the transformation temperature and phase diagram are explained thermodynamically, and the transformation behavior and transformed structures in magnetic fields are discussed.

  10. Solid-phase techniques in blood transfusion serology.

    Beck, M L; Plapp, F V; Sinor, L T; Rachel, J M


    For nearly a century, erythrocyte agglutination has persisted as the most widely used method for the demonstration of antigen-antibody reaction in immunohematology. So far, no other system has been developed which can match its simplicity, versatility, and general reliability. The major disadvantage of agglutination reactions is the lack of an objective endpoint, which has severely hindered attempts to automate routine pretransfusion tests. To overcome this problem, we have designed a series of solid-phase assays for ABO and Rh grouping, antibody screening, compatibility, and hepatitis tests. Each of these solid-phase assays shares a common endpoint of red cell adherence, which is easily interpreted visually or spectrophotometrically. Computer interface permits the automatic interpretation and recording of results. We believe this solid-phase system should finally bring the blood bank laboratory into the age of automation.

  11. Effect of a direct magnetic field on the interfacial microstructure between molten aluminium and solid iron

    HAN Yi; BAN Chun-yan; BA Qi-xian; GUO Shi-jie; WANG Shu-han; CUI Jian-zhong


    Effect of a direct magnetic field on the interfacial microstructure between molten alurninium and solid iron was studied. The intermetallic phases formed in the intermetallic layers were investigated by means of electron probe microanalysis (EPMA) and X-ray diffraction (XRD). It was found that the DC magnetic field can reduce the average thickness of the intermetallic layer and the average aluminium content in the intermetallic layer. Moreover, the intermetallic phases formed in the intermetallic layers are identified as Al3Fe and Al5Fe2 in the absence of the DC magnetic field, while only Al5Fe2 phase present in the presence of the DC magnetic field.


    Yu-ying Li; Jia-song He


    Solid phase transition of the a form crystals to the β form crystals in syndiotactic polystyrene (sPS) samples has occurred in supercritical CO2. This transformation is different from those detected under other conditions. The effects of some factors (e.g. time, temperature, and pressure) on the solid phase transformation of sPS in supercritical CO2 were analyzed in detail. Experimental results show that longer time, higher temperature or higher pressure favors the transformation of the α form crystals to the β form crystals.

  13. A Rapid Solid-phase Synthesis to Soluble Oligothiophene Molecular Wires


    A novel method for the preparation of oligothiophene molecular wires is described via a bi-directional solid-phase synthesis. Using an alternating sequence of bromination and Stille coupling reactions, oligomers were obtained up to the heptamer in excellent yield and purity.

  14. Laser-induced solid-solid phase transition in As under pressure: a theoretical prediction

    Zijlstra, Eeuwe S; Huntemann, Nils; Garcia, Martin E [Theoretische Physik, Universitaet Kassel, Heinrich-Plett-Strasse 40, 34132 Kassel (Germany)], E-mail:


    In arsenic, a pressure-induced solid-solid phase transition from the A7 into the simple cubic structure has been experimentally demonstrated (Beister et al 1990 Phys. Rev. B 41 5535). In this paper, we present calculations, which predict that this phase transition can also be induced by an ultrashort laser pulse in As under pressure. In addition, calculations for the pressure-induced phase transition are presented. Using density functional theory in the generalized gradient approximation, we found that the pressure-induced phase transition takes place at 26.3 GPa and is accompanied by a volume change {delta}V=0.5 a{sub 0}{sup 3} atom{sup -1}. The laser-induced phase transition is predicted for an applied pressure of 23.8 GPa and an absorbed laser energy of 2.8 mRy atom{sup -1}.

  15. All solid-state SBS phase conjugate mirror

    Dane, C.B.; Hackel, L.A.


    A stimulated Brillouin scattering (SBS) phase conjugate laser mirror uses a solid-state nonlinear gain medium instead of the conventional liquid or high pressure gas medium. The concept has been effectively demonstrated using common optical-grade fused silica. An energy threshold of 2.5 mJ and a slope efficiency of over 90% were achieved, resulting in an overall energy reflectivity of >80% for 15 ns, 1 um laser pulses. The use of solid-state materials is enabled by a multi-pass resonant architecture which suppresses transient fluctuations that would otherwise result in damage to the SBS medium. This all solid state phase conjugator is safer, more reliable, and more easily manufactured than prior art designs. It allows nonlinear wavefront correction to be implemented in industrial and defense laser systems whose operating environments would preclude the introduction of potentially hazardous liquids or high pressure gases. 8 figs.

  16. Solid-phase oligosaccharide and glycopeptide synthesis using glycosynthases

    Tolborg, Jakob Fjord; Petersen, Lars; Jensen, Knud Jørgen;


    Enzymatic approaches for the preparation of oligosaccharides are interesting alternatives to traditional chemical synthesis, the main advantage being the regio- and stereoselectivity offered without the need for protecting groups. The use of solid-phase techniques offers easy workup procedures an...

  17. Solid and solution phase combinatorial synthesis of ureas

    Nieuwenhuijzen, JW; Conti, PGM; Ottenheijm, HCJ; Linders, JTM


    An efficient parallel synthesis of ureas based on amino acids is described, both in solution and on solid phase. 1,1'-Carbonylbisbenzotriazole 2 is used as the coupling reagent. The ureas 5 and 10 were obtained in high yield (80-100%) and purity (71-97%). (C) 1998 Elsevier Science Ltd. All rights re

  18. Solid Phase Synthesis of Ethyl β-Substituted Indolepropionates

    刘占祥; 阮秀秀; 黄宪


    A facile solid phase synthesis of ethyl β-substituted indolepropionates is reported. Condensation between indole, polymer-supported cyclic malonic acid ester and aldehyde yielded the trimolecular adducts, which was cleaved by pyridine/EtOH to release the final products in good yield with high purity.

  19. Recent Approaches Toward Solid Phase Synthesis of β-Lactams

    Mandal, Bablee; Ghosh, Pranab; Basu, Basudeb

    Since the discovery of penicillin in 1929, β-lactam antibiotics have been recognized as potentially chemotherapeutic drugs of incomparable effectiveness, conjugating a broad spectrum of activity with very low toxicity. The primary motif azetidin-2-one ring (β-lactam) has been considered as specific pharmacophores and scaffolds. With the advent of combinatorial chemistry and automated parallel synthesis coupled with ample interests from the pharmaceutical industries, recent trends have been driven mostly by adopting solid phase techniques and polymer-supported synthesis of β-lactams. The present survey will present an overview of the developments on the polymer-supported and solid phase techniques for the preparation of β-lactam ring or β-lactam containing antibiotics published over the last decade. Both unsubstituted and substitutions with different functional groups at various positions of β-lactams have been synthesized using solid phase technology. However, Wang resin and application of Staudinger [2+2] cycloaddition reaction have remained hitherto the major choice. It may be expected that other solid phase approaches involving different resins would be developed in the coming years.

  20. Solid-phase synthesis of 3-amino-2-pyrazolines

    Lyngsø, Lars O.; Nielsen, John


    The development of a solid-phase synthesis of 3-amino-2-pyrazolines is described. Conjugate addition of hydrazines to α,β-unsaturated nitriles followed by cyclization yields 3-amino-2-pyrazolines. Acylation or sulfonation of the free amino-group yields a 24 member library of 3-amino-2- pyrazolines....

  1. Solid-phase synthesis of 3-amino-2-pyrazolines

    Nielsen, John


    The development of a solid-phase synthesis of 3-amino-2-pyrazolines is described. Conjugate addition of hydrazines to alpha,beta-unsaturated nitriles followed by cyclization yields 3-amino-2-pyrazolines. Acylation or sulfonation of the free amino-group yields a 24 member library of 3-amino-2...

  2. Solid-phase synthesis of complex and pharmacologically interesting heterocycles

    Nielsen, Thomas Eiland


    Efficient routes for the creation of heterocycles continue to be one of the primary goals for solid-phase synthesis. Recent advances in this field rely most notably on transition-metal-catalysis and N-acyliminium chemistry to mediate a range of cyclization processes for the generation of compounds...

  3. Solid-phase synthesis of 3-amino-2-pyrazolines

    Lyngsø, Lars O.; Nielsen, John


    The development of a solid-phase synthesis of 3-amino-2-pyrazolines is described. Conjugate addition of hydrazines to α,β-unsaturated nitriles followed by cyclization yields 3-amino-2-pyrazolines. Acylation or sulfonation of the free amino-group yields a 24 member library of 3-amino-2- pyrazolines....

  4. Solid-phase synthesis of complex and pharmacologically interesting heterocycles

    Nielsen, Thomas Eiland


    Efficient routes for the creation of heterocycles continue to be one of the primary goals for solid-phase synthesis. Recent advances in this field rely most notably on transition-metal-catalysis and N-acyliminium chemistry to mediate a range of cyclization processes for the generation of compounds...

  5. Solid-phase microextraction for the analysis of biological samples

    Theodoridis, G; Koster, EHM; de Jong, GJ


    Solid-phase microextraction (SPME) has been introduced for the extraction of organic compounds from environmental samples. This relatively new extraction technique has now also gained a lot of interest in a broad field of analysis including food, biological and pharmaceutical samples. SPME has a num

  6. Solid Phase Characterization of Tank 241-C-105 Grab Samples

    Ely, T. M. [Washington River Protection Solutions LLC, Richland, WA (United States); LaMothe, M. E. [Washington River Protection Solutions LLC, Richland, WA (United States); Lachut, J. S. [Washington River Protection Solutions LLC, Richland, WA (United States)


    The solid phase characterization (SPC) of three grab samples from single-shell Tank 241-C-105 (C-105) that were received at the laboratory the week of October 26, 2015, has been completed. The three samples were received and broken down in the 11A hot cells.

  7. Sensitive and fast mutation detection by solid phase chemical cleavage

    Hansen, Lise Lotte; Justesen, Just; Kruse, Torben A


    We have developed a solid phase chemical cleavage method (SpCCM) for screening large DNA fragments for mutations. All reactions can be carried out in microtiterwells from the first amplification of the patient (or test) DNA through the search for mutations. The reaction time is significantly...

  8. In situ transmission electron microscopy of solid-liquid phase transition of silica encapsulated bismuth nanoparticles

    Hu, Jianjun; Hong, Yan; Muratore, Chris; Su, Ming; Voevodin, Andrey A.


    The solid-liquid phase transition of silica encapsulated bismuth nanoparticles was studied by in situ transmission electron microscopy (TEM). The nanoparticles were prepared by a two-step chemical synthesis process involving thermal decomposition of organometallic precursors for nucleating bismuth and a sol-gel process for growing silica. The microstructural and chemical analyses of the nanoparticles were performed using high-resolution TEM, Z-contrast imaging, focused ion beam milling, and X-ray energy dispersive spectroscopy. Solid-liquid-solid phase transitions of the nanoparticles were directly recorded by electron diffractions and TEM images. The silica encapsulation of the nanoparticles prevented agglomeration and allowed particles to preserve their original volume upon melting, which is desirable for applications of phase change nanoparticles with consistently repeatable thermal properties.

  9. Molecularly imprinted solid phase extraction of fluconazole from pharmaceutical formulations.

    Manzoor, S; Buffon, R; Rossi, A V


    This work encompasses a direct and coherent strategy to synthesise a molecularly imprinted polymer (MIP) capable of extracting fluconazole from its sample. The MIP was successfully prepared from methacrylic acid (functional monomer), ethyleneglycoldimethacrylate (crosslinker) and acetonitrile (porogenic solvent) in the presence of fluconazole as the template molecule through a non-covalent approach. The non-imprinted polymer (NIP) was prepared following the same synthetic scheme, but in the absence of the template. The data obtained from scanning electronic microscopy, infrared spectroscopy, thermogravimetric and nitrogen Brunauer-Emmett-Teller plot helped to elucidate the structural as well as the morphological characteristics of the MIP and NIP. The application of MIP as a sorbent was demonstrated by packing it in solid phase extraction cartridges to extract fluconazole from commercial capsule samples through an offline analytical procedure. The quantification of fluconazole was accomplished through UPLC-MS, which resulted in LOD≤1.63×10(-10) mM. Furthermore, a high percentage recovery of 91±10% (n=9) was obtained. The ability of the MIP for selective recognition of fluconazole was evaluated by comparison with the structural analogues, miconazole, tioconazole and secnidazole, resulting in percentage recoveries of 51, 35 and 32%, respectively.

  10. Automated Solid-Phase Radiofluorination Using Polymer-Supported Phosphazenes

    Bente Mathiessen


    Full Text Available The polymer supported phosphazene bases PS-P2tBu and the novel PS-P2PEG allowed for efficient extraction of [18F]F− from proton irradiated [18O]H2O and subsequent radiofluorination of a broad range of substrates directly on the resin. The highest radiochemical yields were obtained with aliphatic sulfonates (69% and bromides (42%; the total radiosynthesis time was 35–45 min. The multivariate analysis showed that the radiochemical yields and purities were controlled by the resin load, reaction temperature, and column packing effects. The resins could be reused several times with the same or different substrates. The fully automated on-column radiofluorination methodology was applied to the radiosynthesis of the important PET radiotracers [18F]FLT and [18F]FDG. The latter was produced with 40% yield on a 120 GBq scale and passed GMP-regulated quality control required for commercial production of [18F]FDG. The combination of compact form factor, simplicity of [18F]F− recovery and processing, and column reusability can make solid phase radiofluorination an attractive radiochemistry platform for the emerging dose-on-demand instruments for bedside production of PET radiotracers.

  11. Ionic liquids in solid-phase microextraction: a review.

    Ho, Tien D; Canestraro, Anthony J; Anderson, Jared L


    Solid-phase microextraction (SPME) has undergone a surge in popularity within the field of analytical chemistry in the past two decades since its introduction. Owing to its nature of extraction, SPME has become widely known as a quick and cost-effective sample preparation technique. Although SPME has demonstrated extraordinary versatility in sampling capabilities, the technique continues to experience a tremendous growth in innovation. Presently, increasing efforts have been directed towards the engineering of novel sorbent material in order to expand the applicability of SPME for a wider range of analytes and matrices. This review highlights the application of ionic liquids (ILs) and polymeric ionic liquids (PILs) as innovative sorbent materials for SPME. Characterized by their unique physico-chemical properties, these compounds can be structurally-designed to selectively extract target analytes based on unique molecular interactions. To examine the advantages of IL and PIL-based sorbent coatings in SPME, the field is reviewed by gathering available experimental data and exploring the sensitivity, linear calibration range, as well as detection limits for a variety of target analytes in the methods that have been developed.

  12. Phase field modeling of flexoelectricity in solid dielectrics

    Chen, H. T.; Zhang, S. D.; Soh, A. K.; Yin, W. Y.


    A phase field model is developed to study the flexoelectricity in nanoscale solid dielectrics, which exhibit both structural and elastic inhomogeneity. The model is established for an elastic homogeneous system by taking into consideration all the important non-local interactions, such as electrostatic, elastic, polarization gradient, as well as flexoelectric terms. The model is then extended to simulate a two-phase system with strong elastic inhomogeneity. Both the microscopic domain structures and the macroscopic effective piezoelectricity are thoroughly studied using the proposed model. The results obtained show that the largest flexoelectric induced polarization exists at the interface between the matrix and the inclusion. The effective piezoelectricity is greatly influenced by the inclusion size, volume fraction, elastic stiffness, and the applied stress. The established model in the present study can provide a fundamental framework for computational study of flexoelectricity in nanoscale solid dielectrics, since various boundary conditions can be easily incorporated into the phase field model.

  13. Distribution of Dechlorinating Bacteria between the Aqueous and Solid Phases

    Cápiro, N. L.; Hatt, J. K.; Wang, Y.; Loeffler, F. E.; Pennell, K. D.


    Microbial monitoring of aquifers relies on nucleic acid biomarker analysis, which is typically performed with biomass recovered from groundwater samples; however, it is unclear what fraction of the target population(s) is associated with groundwater (i.e., planktonic cells) or is attached to solid phases (i.e., biofilms). Understanding how the titer of target organism(s) in groundwater correlates with the true cell titers of the target organism in the aquifer (i.e., planktonic plus attached cells) is critical for a meaningful interpretation of the data, the prediction of bioremediation performance, and the implementation of site management strategies. To evaluate the distribution of active cells between resident solid phase and the aqueous phase, one-dimensional columns were packed under water-saturated conditions with Bio-Dechlor INOCULUM, a PCE-to ethene-dechlorinating bacterial consortium containing both multiple Dehalococcoides (Dhc) strains and Geobacter lovleyi strain SZ (GeoSZ). The columns were packed with two distinct solid matrices: a low organic content sandy Federal Fine Ottawa soil or Appling soil with higher organic matter content. Influent reduced mineral salts medium supplied at a groundwater pore-water velocity of 0.3 m/day contained both 10 mM lactate as electron donor and 0.33 mM PCE as electron acceptor. Routine collection of biomass from column side ports and effluent samples measured the titers of target cells in the aqueous phase and determined when steady state conditions had been reached. A second set of column experiments evaluated delivery and filtration effects by the solid matrix (i.e., Federal Fine Ottawa sand versus Appling soil) under the same conditions except that electron donor or acceptor were omitted (no growth conditions). Quantitative real-time PCR (qPCR) analysis using Dhc and GeoSZ 16S rRNA gene-targeted primer and probe sets determined the planktonic cell counts, and destructive sampling of the columns allowed measurement

  14. Solid-phase synthesis of molecularly imprinted nanoparticles.

    Canfarotta, Francesco; Poma, Alessandro; Guerreiro, Antonio; Piletsky, Sergey


    Molecularly imprinted polymers (MIPs) are synthetic materials, generally based on acrylic or methacrylic monomers, that are polymerized in the presence of a specific target molecule called the 'template' and capable of rebinding selectively to this target molecule. They have the potential to be low-cost and robust alternatives to biomolecules such as antibodies and receptors. When prepared by traditional synthetic methods (i.e., with free template in solution), their usefulness has been limited by high binding site heterogeneity, the presence of residual template and the fact that the production methods are complex and difficult to standardize. To overcome some of these limitations, we developed a method for the synthesis of MIP nanoparticles (nanoMIPs) using an innovative solid-phase approach, which relies on the covalent immobilization of the template molecules onto the surface of a solid support (glass beads). The obtained nanoMIPs are virtually free of template and demonstrate high affinity for the target molecule (e.g., melamine and trypsin in our published work). Because of an affinity separation step performed on the solid phase after polymerization, poor binders and unproductive polymer are removed, so the final product has more uniform binding characteristics. The overall protocol, starting from the immobilization of the template onto the solid phase and including the purification and characterization of the nanoparticles, takes up to 1 week.

  15. Analysis of illicit drugs by direct ablation of solid samples.

    Bermúdez, Celina; Cabezas, Carlos; Mata, Santiago; Berdakin, Matias; Tejedor, Jesús M; Alonso, José L


    Analysis of illicit drugs arises as an important field of work given the high social impacts presented by drugs in the modern society. Direct laser ablation of solid compounds allows their analysis without sampling or preparation procedures. For that purpose, an experimental set-up that combines laser ablation with time-of- flight mass spectrometry has been constructed very recently to perform studies on the mass spectra of such drugs as 3,4-methylenedioxy-N-methylamphetamine, commonly known as MDMA or ecstasy. Analysis of the observed fragmentation pattern in mass spectra may elucidate the ablation-induced photofragmentation phenomena produced, which differ from those previously observed with conventional ionization methods.

  16. Synthesis of Non-molecular Nitrogen Phases at Mbar Pressures by Direct Laser-heating

    Lipp, M J; Klepeis, J P; Baer, B J; Cynn, H; Evans, W J; Iota, V; Yoo, C


    Direct laser heating of molecular N2 to above 1400 K at 120-130 GPa results in the formation of a reddish amorphous phase and a transparent crystalline solid above 2000 K. Raman and x-ray data confirm that the transparent phase is cubic-gauche nitrogen (cg-N), while the reddish color of the amorphous phase might indicate the presence of N=N dish bonds. The quenched amorphous phase is stable down to at least 70GPa, analogous to cg-N, and could be a new non-molecular phase or an extension of the already known {eta}-phase. A chemo-physical phase diagram is presented which emphasizes the difference between pressure- and temperature-induced transitions from molecular to non-molecular solids, as found in other low Z systems.

  17. Studies in Solid Phase Peptide Synthesis: A Personal Perspective

    Mitchell, A R


    By the early 1970s it had became apparent that the solid phase synthesis of ribonuclease A could not be generalized. Consequently, virtually every aspect of solid phase peptide synthesis (SPPS) was reexamined and improved during the decade of the 1970s. The sensitive detection and elimination of possible side reactions (amino acid insertion, N{sup {alpha}}-trifluoroacetylation, N{sup {alpha}{var_epsilon}}-alkylation) was examined. The quantitation of coupling efficiency in SPPS as a function of chain length was studied. A new and improved support for SPPS, the 'PAM-resin', was prepared and evaluated. These and many other studies from the Merrifield laboratory and elsewhere increased the general acceptance of SPPS leading to the 1984 Nobel Prize in Chemistry for Bruce Merrifield.

  18. Entransy dissipation minimization for liquid-solid phase change processes


    The liquid-solid phase change process of a simple one-dimensional slab is studied in this paper.By taking entransy dissipation minimization as optimization objective,the optimal external reservoir temperature profiles are derived by using optimal control theory under the condition of a fixed freezing or melting time.The entransy dissipation corresponding to the optimal heat exchange strategies of minimum entransy dissipation is 8/9 of that corresponding to constant reservoir temperature operations,which is independent of all system parameters.The obtained results for entransy dissipation minimization are also compared with those obtained for the optimal heat exchange strategies of minimum entropy generation and constant reservoir temperature operations by numerical examples.The obtained results can provide some theoretical guidelines for the choice of optimal cooling or heating strategy in practical liquid-solid phase change processes.

  19. Semi-automated microwave assisted solid-phase peptide synthesis

    Pedersen, Søren Ljungberg

    with microwaves for SPPS has gained in popularity as it for many syntheses has provided significant improvement in terms of speed, purity, and yields, maybe especially in the synthesis of long and "difficult" peptides. Thus, precise microwave heating has emerged as one new parameter for SPPS, in addition...... to coupling reagents, resins, solvents etc. We have previously reported on microwave heating to promote a range of solid-phase reactions in SPPS. Here we present a new, flexible semi-automated instrument for the application of precise microwave heating in solid-phase synthesis. It combines a slightly modified...... Biotage Initiator microwave instrument, which is available in many laboratories, with a modified semi-automated peptide synthesizer from MultiSynTech. A custom-made reaction vessel is placed permanently in the microwave oven, thus the reactor does not have to be moved between steps. Mixing is achieved...

  20. Solid-Phase Organic Synthesis and Catalysis: Some Recent Strategies Using Alumina, Silica, and Polyionic Resins

    Basudeb Basu


    Full Text Available Solid-phase organic synthesis (SPOS and catalysis have gained impetus after the seminal discovery of Merrifield’s solid-phase peptide synthesis and also because of wide applicability in combinatorial and high throughput chemistry. A large number of organic, inorganic, or organic-inorganic hybrid materials have been employed as polymeric solid supports to promote or catalyze various organic reactions. This review article provides a concise account on our approaches involving the use of (i alumina or silica, either having doped with metal salts or directly, and (ii polyionic resins to either promote various organic reactions or to immobilize reagents/metal catalysts for subsequent use in hydrogenation and cross-coupling reactions. The reaction parameters, scopes, and limitations, particularly in the context of green chemistry, have been highlighted with pertinent approaches by other groups.

  1. Indigenous microbial capability in solid manure residues to start-up solid-phase anaerobic digesters.

    Yap, S D; Astals, S; Jensen, P D; Batstone, D J; Tait, S


    Batch solid-phase anaerobic digestion is a technology for sustainable on-farm treatment of solid residues, but is an emerging technology that is yet to be optimised with respect to start-up and inoculation. In the present study, spent bedding from two piggeries (site A and B) were batch digested at total solids (TS) concentration of 5, 10 and 20% at mesophilic (37°C) and thermophilic (55°C) temperatures, without adding an external inoculum. The results showed that the indigenous microbial community present in spent bedding was able to recover the full methane potential of the bedding (140±5 and 227±6L CH4 kgVSfed(-1) for site A and B, respectively), but longer treatment times were required than for digestion with an added external inoculum. Nonetheless, at high solid loadings (i.e. TS level>10%), the digestion performance was affected by chemical inhibition due to ammonia and/or humic acid. Thermophilic temperatures did not influence digestion performance but did increase start-up failure risk. Further, inoculation of residues from the batch digestion to subsequent batch enhanced start-up and achieved full methane potential recovery of the bedding. Inoculation with liquid residue (leachate) was preferred over a solid residue, to preserve treatment capacity for fresh substrate. Overall, the study highlighted that indigenous microbial community in the solid manure residue was capable of recovering full methane potential and that solid-phase digestion was ultimately limited by chemical inhibition rather than lack of suitable microbial community. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Hyperdoping silicon with selenium: solid vs. liquid phase epitaxy

    Zhou, Shengqiang; Liu, Fang; Prucnal, S.; Gao, Kun; Khalid, M.; Baehtz, C.; Posselt, M.; Skorupa, W.; Helm, M


    Chalcogen-hyperdoped silicon shows potential applications in silicon-based infrared photodetectors and intermediate band solar cells. Due to the low solid solubility limits of chalcogen elements in silicon, these materials were previously realized by femtosecond or nanosecond laser annealing of implanted silicon or bare silicon in certain background gases. The high energy density deposited on the silicon surface leads to a liquid phase and the fast recrystallization velocity allows trapping o...

  3. Chromatography, solid-phase extraction, and capillary electrochromatography with MIPs.

    Tóth, Blanka; Horvai, George


    Most analytical applications of molecularly imprinted polymers are based on their selective adsorption properties towards the template or its analogs. In chromatography, solid phase extraction and electrochromatography this adsorption is a dynamic process. The dynamic process combined with the nonlinear adsorption isotherm of the polymers and other factors results in complications which have limited the success of imprinted polymers. This chapter explains these problems and shows many examples of successful applications overcoming or avoiding the problems.

  4. Simulating confined swirling gas-solid two phase jet

    金晗辉; 夏钧; 樊建人; 岑可法


    A k-ε-kp multi-fluid model was used to simulate confined swirling gas-solid two phase jet comprised of particle-laden flow from a center tube and a swirling air stream entering the test section from the coaxial annular. After considering the drag force between the two phases and gravity, a series of numerical simulations of the two-phase flow of 30μm, 45μm, 60μm diameter particles were performed on a x×r=50×50 mesh grid respectively. The results showed that the k-ε-kp multi-fluid model can be applied to predict moderate swirling multi-phase flow. When the particle diameter is large, the collision of the particles with the wall will influence the prediction accuracy. The bigger the diameter of the particles, the stronger the collision with the wall, and the more obvious the difference between measured and calculated results.

  5. Application of solid phase microextraction on dental composite resin analysis.

    Wang, Ven-Shing; Chang, Ta-Yuan; Lai, Chien-Chen; Chen, San-Yue; Huang, Long-Chen; Chao, Keh-Ping


    A direct immersion solid phase microextraction (DI-SPME) method was developed for the analysis of dentin monomers in saliva. Dentine monomers, such as triethylene glycol dimethacrylate (TEGDMA), urethane dimethacrylate (UDMA) and 2,2-bis-[4-(2-hydroxy-3-methacryloyloxypropoxy) phenyl]-propane (Bis-GMA), have a high molecular weight and a low vapor pressure. The polydimethylsiloxane/divinylbenzene (PDMS/DVB) fiber with a medium polarity was employed for DI-SPME, and 215 nm of detection wavelength was found to be optimum in the chromatogram of HPLC measurement. The calibration range for DI-SPME was 0.30-300 μg/mL with correlation coefficients (r) greater than 0.998 for each analyte. The DI-SPME method achieved good accuracy (recovery 96.1-101.2%) and precision (2.30-8.15% CV) for both intra- and inter-day assays of quality control samples for three target compounds. Method validation was performed on standards dissolved in blank saliva, and there was no significant difference (p>0.2) between the DI-SPME method and the liquid injection method. However, the detection limit of DI-SPME was as low as 0.03, 0.27 and 0.06 μg/mL for TEGDMA, UDMA and Bis-GMA, respectively. Real sample analyses were performed on commercial dentin products after curing for the leaching measurement. In summary, DI-SPME is a more sensitive method that requires less sample pretreatment procedures to measure the resin materials leached in saliva.

  6. Synthesis of silicon carbide nanowires by solid phase source chemical vapor deposition

    NI Jie; LI Zhengcao; ZHANG Zhengjun


    In this paper,we report a simple approach to synthesize silicon carbide(SiC)nanowires by solid phase source chemical vapor deposition(CVD) at relatively low temperatures.3C-SiC nanowires covered by an amorphous shell were obtained on a thin film which was first deposited on silicon substrates,and the nanowires are 20-80 am in diameter and several μm in length,with a growth direction of[200].The growth of the nanowires agrees well on vapor-liquid-solid (VLS)process and the film deposited on the substrates plays an important role in the formation of nanowires.

  7. Two phase continuous digestion of solid manure on-farm

    Schaefer, W.; Lehto, M. [MTT Agrifood Research Finland, Vihti (Finland). Animal Production Research; Evers, L.; Granstedt, A. [Biodynamic Research Inst., Jaerna (Sweden)


    Present commercially available biogas plants are mainly suitable for slurry and co-substrates. Cattle, horse and poultry farms using a solid manure chain experience a crucial competitive disadvantage, because conversion to slurry technology requires additional investments. Based on the technological progress of anaerobic digestion of municipal solid waste, so called 'dry fermentation' prototype plants were developed for anaerobic digestion of organic material containing 15-50% total solids (Hoffman, 2001). These plants show added advantages compared to slurry digestion plants: Less reactor volume, less process energy, less transport capacity, less odour emissions. On-farm research (Gronauer and Aschmann, 2004; Kusch and Oechsner, 2004) and prototype research (Linke, 2004) on dry fermentation in batch reactors show that loading and discharging of batch reactors remains difficult and/or time-consuming compared to slurry reactors. Additionally a constant level of gas generation requires offset operation of several batch reactors. Baserga et al. (1994) developed a pilot plant of 9.6 m{sup 3} capacity for continuous digestion of solid beef cattle manure on-farm. However, on-farm dry fermentation plants are not common and rarely commercially available. We assume that lack of tested technical solutions and scarceness of on-farm research results are the main reason for low acceptance of dry fermentation technology on-farm. We report about an innovative two phase farm-scale biogas plant. The plant continuously digests dairy cattle manure and organic residues of the farm and the surrounding food processing units. The two phase reactor technology was chosen for two reasons: first it offers the separation of a liquid fraction and a solid fraction for composting after hydrolysis and secondly the methanation of the liquid fraction using fixed film technology results in a very short hydraulic retention time, reduction in reactor volume, and higher methane content of the

  8. Preparation of bioconjugates by solid-phase conjugation to ion exchange matrix-adsorbed carrier proteins

    Houen, G.; Olsen, D.T.; Hansen, P.R.;


    A solid-phase conjugation method utilizing carrier protein bound to an ion exchange matrix was developed. Ovalbumin was adsorbed to an anion exchange matrix using a batch procedure, and the immobilized protein was then derivatized with iodoacetic acid N-hydroxysuccinimid ester. The activated......, and immunization experiments with the eluted conjugates showed that the more substituted conjugates gave rise to the highest titers of glutathione antibodies. Direct immunization with the conjugates adsorbed to the ion exchange matrix was possible and gave rise to high titers of glutathione antibodies. Conjugates...... of ovalbumin and various peptides were prepared in a similar manner and used for production of peptide antisera by direct immunization with the conjugates bound to the ion exchanger. Advantages of the method are its solid-phase nature, allowing fast and efficient reactions and intermediate washings...

  9. Phase field modeling and simulation of three-phase flow on solid surfaces

    Zhang, Qian; Wang, Xiao-Ping


    Phase field models are widely used to describe the two-phase system. The evolution of the phase field variables is usually driven by the gradient flow of a total free energy functional. The generalization of the approach to an N phase (N ≥ 3) system requires some extra consistency conditions on the free energy functional in order for the model to give physically relevant results. A projection approach is proposed for the derivation of a consistent free energy functional for the three-phase Cahn-Hilliard equations. The system is then coupled with the Navier-Stokes equations to describe the three-phase flow on solid surfaces with moving contact line. An energy stable scheme is developed for the three-phase flow system. The discrete energy law of the numerical scheme is proved which ensures the stability of the scheme. We also show some numerical results for the dynamics of triple junctions and four phase contact lines.

  10. Direct Carbon Fuel Cell System Utilizing Solid Carbonaceous Fuels

    Turgut Gur


    This 1-year project has achieved most of its objective and successfully demonstrated the viability of the fluidized bed direct carbon fuel cell (FB-DCFC) approach under development by Direct Carbon technologies, LLC, that utilizes solid carbonaceous fuels for power generation. This unique electrochemical technology offers high conversion efficiencies, produces proportionately less CO{sub 2} in capture-ready form, and does not consume or require water for gasification. FB-DCFC employs a specialized solid oxide fuel cell (SOFC) arrangement coupled to a Boudouard gasifier where the solid fuel particles are fluidized and reacted by the anode recycle gas CO{sub 2}. The resulting CO is electrochemically oxidized at the anode. Anode supported SOFC structures employed a porous Ni cermet anode layer, a dense yttria stabilized zirconia membrane, and a mixed conducting porous perovskite cathode film. Several kinds of untreated solid fuels (carbon and coal) were tested in bench scale FBDCFC prototypes for electrochemical performance and stability testing. Single cells of tubular geometry with active areas up to 24 cm{sup 2} were fabricated. The cells achieved high power densities up to 450 mW/cm{sup 2} at 850 C using a low sulfur Alaska coal char. This represents the highest power density reported in the open literature for coal based DCFC. Similarly, power densities up to 175 mW/cm{sup 2} at 850 C were demonstrated with carbon. Electrical conversion efficiencies for coal char were experimentally determined to be 48%. Long-term stability of cell performance was measured under galvanostatic conditions for 375 hours in CO with no degradation whatsoever, indicating that carbon deposition (or coking) does not pose any problems. Similar cell stability results were obtained in coal char tested for 24 hours under galvanostatic conditions with no sign of sulfur poisoning. Moreover, a 50-cell planar stack targeted for 1 kW output was fabricated and tested in 95% CO (balance CO{sub 2

  11. Studies on solid-solid phase transitions of polyols by infrared spectroscopy

    Feng, H.; Liu, X.; He, S.; Wu, K.; Zhang, J. [Department of Chemistry, Hebei Normal University, Shijiazhuang (China)


    This paper chiefly deals with the properties of polyols - a kind of energy storage material, by IR spectra. A series of infrared spectra at various temperatures were obtained for pentaerythritol (PE), pentaglycerine (PG), neopentylglycol (NPG) and their mixture NPG/PG. The experimental results (the shifts of -OH absorption band in IR spectra) support the solid-solid phase transition mechanism, which involves the reversible breaking of nearest-neighbor hydrogen bonds in the molecular crystals at transformation temperature. The correlation between the wave number shifts and the temperatures of phase transition is proposed in this paper. Finally, by means of infrared spectroscopy experiments, it is shown that aging has a great influence on the thermal properties of polyol mixtures.

  12. Micro versus macro solid phase extraction for monitoring water contaminants: a preliminary study using trihalomethanes.

    Alexandrou, Lydon D; Spencer, Michelle J S; Morrison, Paul D; Meehan, Barry J; Jones, Oliver A H


    Solid phase extraction is one of the most commonly used pre-concentration and cleanup steps in environmental science. However, traditional methods need electrically powered pumps, can use large volumes of solvent (if multiple samples are run), and require several hours to filter a sample. Additionally, if the cartridge is open to the air volatile compounds may be lost and sample integrity compromised. In contrast, micro cartridge based solid phase extraction can be completed in less than 2 min by hand, uses only microlitres of solvent and provides comparable concentration factors to established methods. It is also an enclosed system so volatile components are not lost. The sample can also be eluted directly into a detector (e.g. a mass spectrometer) if required. However, the technology is new and has not been much used for environmental analysis. In this study we compare traditional (macro) and the new micro solid phase extraction for the analysis of four common volatile trihalomethanes (trichloromethane, bromodichloromethane, dibromochloromethane and tribromomethane). The results demonstrate that micro solid phase extraction is faster and cheaper than traditional methods with similar recovery rates for the target compounds. This method shows potential for further development in a range of applications.

  13. Determination of zinc in environmental samples by solid phase spectrophotometry: optimization and validation study

    Molina, Mar??a Francisca; Nechar, Mounir; Bosque-Sendra, Juan M.


    A simple and specific solid-phase spectrophotometric (SPS) determination of zinc in ??g dm-3 level has been developed based on the reaction of Zn(II) with 4-(2-pyridylazo)resorcinol (PAR) in the presence of potassium iodide; the product was then fixed on an anionic exchanger. The absorbance of the gel, packed in a 1 mm cell, is measured directly. PAR and KI concentrations were optimized simultaneously using response surface methodology (RSM) from sequential experimental Doehlert designs. The ...

  14. Dynamics of Vibrio cholerae abundance in Austrian saline lakes, assessed with quantitative solid-phase cytometry


    International audience; In order to elucidate the main predictors of Vibrio cholerae dynamics and to estimate the risk of Vibrio cholera-related diseases, a recently developed direct detection approach based on fluorescence in situ hybridization and solid-phase cytometry (CARD-FISH/ SPC) was applied in comparison to cultivation for water samples from the lake Neusiedler See, Austria and three shallow alkaline lakes over a period of 20 months. Vibrio cholerae attached to crustacean zoo-plankto...

  15. Solid-phase cloning for high-throughput assembly of single and multiple DNA parts

    Lundqvist, Magnus; Edfors, Fredrik; Sivertsson, Åsa


    We describe solid-phase cloning (SPC) for high-throughput assembly of expression plasmids. Our method allows PCR products to be put directly into a liquid handler for capture and purification using paramagnetic streptavidin beads and conversion into constructs by subsequent cloning reactions. We...... at an average success rate above 80%. We report on several applications for SPC and we suggest it to be particularly suitable for high-throughput efforts using laboratory workstations....

  16. Determination of Trace Amount of Yttrium with Bromopyrogallol Red by Solid-phase Spectrophotometry


    A simple and sensitive method for the determination of trace amount of yttrium by solid-phase spectrophotometry has been studied. Yttrium can form a 1∶1 complex with bromopyrogallol red (BPR) on resin, which was determined directly at 605 nm, pH=6.5. It has a highly sensitivity ( = 6.3€?06) which is 300-fold higher than the corresponding spectrophotometry in solution. The method was applied to the determination of yttrium in churchite.

  17. Determination of formaldehyde in Brazilian alcohol fuels by flow-injection solid phase spectrophotometry

    Teixeira, Leonardo Sena Gomes; Leão, Elsimar S.; Dantas,Alailson Falcão; Pinheiro, Heloísa Lúcia C.; Costa, Antonio Celso Spinola; Andrade,Jailson Bittencourt de


    p. 711–715 In thiswork, a solid phase spectrophotometric method in association with flowinjection analysis for formaldehyde determination has been developed with direct measurement of light-absorption in C18 material. The 3,5-diacetyl-1,4-dihydrolutidine produced from the reaction between formaldehyde and fluoral P was quantitatively retained on C18 support and the spectrophotometric detection was performed simultaneously at 412 nm. The retained complex was quickly eluted from C18 mater...

  18. Profilometry of three-dimensional discontinuous solids by combining two-steps temporal phase unwrapping, co-phased profilometry and phase-shifting interferometry

    Servin, Manuel; Padilla, Moises; Garnica, Guillermo; Gonzalez, Adonai


    In this work we review and combine two techniques that have been recently published for three-dimensional (3D) fringe projection profilometry and phase unwrapping, namely: co-phased profilometry and 2-steps temporal phase-unwrapping. By combining these two methods we get a more accurate, higher signal-to-noise 3D profilometer for discontinuous industrial objects. In single-camera single-projector (standard) profilometry, the camera and the projector must form an angle between them. The phase-sensitivity of the profilometer depends on this angle, so it cannot be avoided. This angle produces regions with self-occluding shadows and glare from the solid as viewed from the camera's perspective, making impossible the demodulation of the fringe-pattern there. In other words, the phase data is undefined at those shadow regions. As published recently, this limitation can be solved by using several co-phased fringe-projectors and a single camera. These co-phased projectors are positioned at different directions towards the object, and as a consequence most shadows are compensated. In addition to this, most industrial objects are highly discontinuous, which precludes the use of spatial phase-unwrappers. One way to avoid spatial unwrapping is to decrease the phase-sensitivity to a point where the demodulated phase is bounded to one lambda, so the need for phase-unwrapping disappears. By doing this, however, the recovered non-wrapped phase contains too much harmonic distortion and noise. Using our recently proposed two-step temporal phase-unwrapping technique, the high-sensitivity phase is unwrapped using the low-frequency one as initial gross estimation. This two-step unwrapping technique solves the 3D object discontinuities while keeping the accuracy of the high-frequency profilometry data. In scientific research, new art are derived as logical and consistent result of previous efforts in the same direction. Here we present a new 3D-profilometer combining these two recently

  19. Solid-Phase Preparation and Characterization of Chitosan

    GaoLe-ping; DuYu-min; ZhangDao-bin; ShiXiao-wen; ZhanHuai-yu; SongWen-hua


    Chitosan was prepared with stressing method by blending chitin and solid alkali in a single-screw extruder at given temperature and characterized by potentiometric titration, gel permeation chromatography (GPC), infrared spectrum (IR) and carborr13 magnetic resonance sperctroscopy (13C NMR). Chitosan with a deacetylation degree (DD) of 76. 1% was obtained at a mass ratio 0.2 : 1 : 1 for H20/chitin/NaOH at 160℃ for 12 mirL Compared to conventional solution method(usually 1 : 10 for chitin/NaOH), the alkali assumption greatly decreased. Molecular weight of chitosan obtained by solid-phase method(S3,M. 1.54 X 10s ) was lower than that obtained by suspension method(Y2,Mw3. 34×105). During deacetylation, molecular weight decreased with high reaction temperature and long reaction time but remained same at different initial ratios of NaOH/chitirL It might be concluded that degradation of chitosan was caused by breakout of the main chain of the oxidized chitosan catalyzed by alkali during the deactylation. IR and 13C NMR showed that structures of chitosans prepared by solid-phase method were not changed.

  20. Thermodynamic phase behavior of API/polymer solid dispersions.

    Prudic, Anke; Ji, Yuanhui; Sadowski, Gabriele


    To improve the bioavailability of poorly soluble active pharmaceutical ingredients (APIs), these materials are often integrated into a polymer matrix that acts as a carrier. The resulting mixture is called a solid dispersion. In this work, the phase behaviors of solid dispersions were investigated as a function of the API as well as of the type and molecular weight of the carrier polymer. Specifically, the solubility of artemisinin and indomethacin was measured in different poly(ethylene glycol)s (PEG 400, PEG 6000, and PEG 35000). The measured solubility data and the solubility of sulfonamides in poly(vinylpyrrolidone) (PVP) K10 and PEG 35000 were modeled using the perturbed-chain statistical associating fluid theory (PC-SAFT). The results show that PC-SAFT predictions are in a good accordance with the experimental data, and PC-SAFT can be used to predict the whole phase diagram of an API/polymer solid dispersion as a function of the kind of API and polymer and of the polymer's molecular weight. This remarkably simplifies the screening process for suitable API/polymer combinations.

  1. Novel solidsolid phase change material based on polyethylene glycol and cellulose used for temperature stabilisation

    Wojda Marta


    Full Text Available Thermal management is one of crucial issues in the development of modern electronic devices. In the recent years interest in phase change materials (PCMs as alternative cooling possibility has increased significantly. Preliminary results concerning the research into possibility of the use of solid-solid phase change materials (S-S PCMs for stabilisation temperature of electronic devices has been presented in the paper. Novel solid-solid phase change material based on polyethylene glycol and cellulose has been synthesized. Attempt to improve its thermal conductivity has been taken. Material has been synthesized for the purpose of stabilisation of temperature of electronic devices.

  2. Direct determination of three-phase contact line properties on nearly molecular scale

    Winkler, P. M.; McGraw, R. L.; Bauer, P. S.; Rentenberger, C.; Wagner, P. E.


    Wetting phenomena in multi-phase systems govern the shape of the contact line which separates the different phases. For liquids in contact with solid surfaces wetting is typically described in terms of contact angle. While in macroscopic systems the contact angle can be determined experimentally, on the molecular scale contact angles are hardly accessible. Here we report the first direct experimental determination of contact angles as well as contact line curvature on a scale of the order of ...

  3. Solid Phase Peptide Synthesis of Fusukang for AIDS

    甘一如; 戴琦; 张雪竹; 高晨昊


    A 36-residue peptide is designed to cure acquired immunodeficiency syndrome(AIDS), and is synthesized by the manual solid phase peptide synthesis technique. Different reaction conditions of the synthesis process were discussed. Stirring efficiency of mechanics and nitrogen was compared. The mechanical method displays a predominant performance. Although the coupling efficiencies of diisopropylcarbodiimide(DIC) and dicyclohexylcarbodiimide(DCC) are virtually identical, DIC offers several advantages over DCC in practice due to different physical characters. Wash conditions after deprotection and coupling were investigated to monitor washing efficiency. 0.369 2 g crude peptide was obtained.

  4. Solid-phase colorimetric method for the quantification of fucoidan.

    Lee, Jung Min; Shin, Z-U; Mavlonov, Gafurjon T; Abdurakhmonov, Ibrokhim Y; Yi, Tae-Hoo


    We described the simple, selective, and rapid method for determination of fucoidans using methylene blue staining of sulfated polysaccharides, immobilized into filter paper and consequent optic density (at A (663) nm) measurement of the eluted dye from filter paper. This solid-phase method allows selective determination of 1-20 μg fucoidan in presence of potentially interfering compounds (alginic acid, DNA, salts, proteins, and detergents). Further, we demonstrated the alternative way of using image processing software for fucoidan quantification without extraction of methylene blue dye from stained spots of fucoidan-dye complex.

  5. Anisotropic solid-liquid interface kinetics in silicon: an atomistically informed phase-field model

    Bergmann, S.; Albe, K.; Flegel, E.; Barragan-Yani, D. A.; Wagner, B.


    We present an atomistically informed parametrization of a phase-field model for describing the anisotropic mobility of liquid-solid interfaces in silicon. The model is derived from a consistent set of atomistic data and thus allows to directly link molecular dynamics and phase field simulations. Expressions for the free energy density, the interfacial energy and the temperature and orientation dependent interface mobility are systematically fitted to data from molecular dynamics simulations based on the Stillinger-Weber interatomic potential. The temperature-dependent interface velocity follows a Vogel-Fulcher type behavior and allows to properly account for the dynamics in the undercooled melt.


    E.Q. Xie; W.W. Wang; N. Jiang; D.Y. He


    Manganese silicide MnSi2-x thin films have been prepared on n-type silicon substratesthrough solid phase reaction. The heterostructures were analyzed by X-ray diffraction,Rutherford backscattering spectroscopy, Fourier transform infrared transmittance spec-troscopy and the four-point probe technique. The results show that two manganese sili-cides have been formed sequentially via the reaction of thin layer Mn with Si substrateat different irradiation annealing stages, i.e., MnSi at 450℃ and MnSi1.73 at 550℃.MnSi1.73 phase exhibits preferred growth after irradiation with infrared. In situ four-point probe measurements of sheet resistance during infrared irradiation annealingshow that nucleation of MnSi and phase transformation of MnSi to MnSi1. 73 occur at410℃ and 530℃, respectively; the MnSi phase shows metallic behavior, while MnSi1.73exhibits semiconducting behavior. Characteristic phonon bands of MnSi2-x silicides,which can be used for phase identification along with conventional XRD techniques,have been observed by FTIR spectroscopy.


    Ning Yang; Wei Wang; Wei Ge; Jinghai Li


    @@ Introduction Gas-solid two-phase flow is often encountered in chemical reactors for the process industry. For industrial users, design, scale-up, control and optimization for these reactors require a good understanding of the hydrodynamics of gas-solid two-phase flow. For researchers, exploration and prediction of the complex phenomena call for a good comprehension of the heterogeneous structure and of the dominant mechanisms of gas-solid and solid-solid interactions.

  8. Direct Solid-State Conversion of Recyclable Metals and Alloys

    Kiran Manchiraju


    Friction Stir Extrusion (FSE) is a novel energy-efficient solid-state material synthesis and recycling technology capable of producing large quantity of bulk nano-engineered materials with tailored, mechanical, and physical properties. The novelty of FSE is that it utilizes the frictional heating and extensive plastic deformation inherent to the process to stir, consolidate, mechanically alloy, and convert the powders, chips, and other recyclable feedstock materials directly into useable product forms of highly engineered materials in a single step (see Figure 1). Fundamentally, FSE shares the same deformation and metallurgical bonding principles as in the revolutionary friction stir welding process. Being a solid-state process, FSE eliminates the energy intensive melting and solidification steps, which are necessary in the conventional metal synthesis processes. Therefore, FSE is highly energy-efficient, practically zero emissions, and economically competitive. It represents a potentially transformational and pervasive sustainable manufacturing technology for metal recycling and synthesis. The goal of this project was to develop the technological basis and demonstrate the commercial viability of FSE technology to produce the next generation highly functional electric cables for electricity delivery infrastructure (a multi-billion dollar market). Specific focus of this project was to (1) establish the process and material parameters to synthesize novel alloys such as nano-engineered materials with enhanced mechanical, physical, and/or functional properties through the unique mechanical alloying capability of FSE, (2) verifying the expected major energy, environmental, and economic benefits of FSE technology for both the early stage 'showcase' electric cable market and the anticipated pervasive future multi-market applications across several industry sectors and material systems for metal recycling and sustainable manufacturing.

  9. Electrostatic levitation studies of supercooled liquids and metastable solid phases

    Rustan, Gustav Errol

    been carried out to study the metastable phase formation in an Fe83B17 near eutectic alloy. Initial supercooling measurements using the ISU-ESL identified the formation of three metastable phases: a precipitate phase that shows stable coexistence with the deeply supercooled liquid, and two distinct bulk solidification phases. To identify the structure of the metastable phases, the Washington University Beamline ESL (WU-BESL) has been used to perform in-situ high energy x-ray diffraction measurements of the metastable phases. Based on the x-ray results, the precipitate phase has been identified as bcc-Fe, and the more commonly occurring bulk solidification product has been found to be a two-phase mixture of Fe23B6 plus fcc-Fe, which appears, upon cooling, to transform into a three phase mixture of Fe23B6, bcc-Fe, and an as-yet unidentified phase, with the transformation occurring at approximately the expected fcc-to-bcc transformation temperature of pure Fe. To further characterize the multi-phase metastable alloy, the ISU-ESL has been used to perform measurements of volume thermal expansion via the videographic technique, as well as RF susceptibility via the TDO technique. The results of the thermal expansion and susceptibility data have been found to be sensitive indicators of additional structural changes that may be occurring in the metastable solid at temperatures below 1000 K, and the susceptibility data has revealed that three distinct ferromagnetic phase transitions take place within the multi-phase mixture. Based on these results, it has been hypothesized that there may be an additional transformation taking place that leads to the formation of either bct- or o-Fe3B in addition to the Fe23B6 phase, although further work is required to test this hypothesis.

  10. Nucleation of the diamond phase in aluminium-solid solutions

    Hornbogen, E.; Mukhopadhyay, A. K.; Starke, E. A., Jr.


    Precipitation was studied from fcc solid solutions with silicon, germanium, copper and magnesium. Of all these elements only silicon and germanium form diamond cubic (DC) precipitates in fcc Al. Nucleation of the DC structure is enhanced if both types of atom are dissolved in the fcc lattice. This is interpreted as due to atomic size effects in the prenucleation stage. There are two modes of interference of fourth elements with nucleation of the DC phase in Al + Si, Ge. The formation of the DC phase is hardly affected if the atoms (for example, copper) are rejected from the (Si, Ge)-rich clusters. If additional types of atom are attracted by silicon and/or germanium, DC nuclei are replaced by intermetallic compounds (for example Mg2Si).

  11. Powder metallurgy: Solid and liquid phase sintering of copper

    Sheldon, Rex; Weiser, Martin W.


    Basic powder metallurgy (P/M) principles and techniques are presented in this laboratory experiment. A copper based system is used since it is relatively easy to work with and is commercially important. In addition to standard solid state sintering, small quantities of low melting metals such as tin, zinc, lead, and aluminum can be added to demonstrate liquid phase sintering and alloy formation. The Taguchi Method of experimental design was used to study the effect of particle size, pressing force, sintering temperature, and sintering time. These parameters can be easily changed to incorporate liquid phase sintering effects and some guidelines for such substitutions are presented. The experiment is typically carried out over a period of three weeks.

  12. Preparation of the initial solid liquid interface and melt in directional solidification

    Nguyen Thi, H.; Drevet, B.; Debierre, J. M.; Camel, D.; Dabo, Y.; Billia, B.


    The preparation of the initial conditions (solid-liquid interface morphology and solute segregation in the liquid phase) on which growth is started is a very critical step in directional-solidification experiments. Dedicated experiments on Al-1.5 wt% Ni consisting in directional melting followed by thermal stabilisation with different lengths, show that precise control is in practice not straightforward. Indeed, in the mushy zone created by melting the original solid sample, temperature gradient zone melting (TGZM) causes migration of solute-rich liquid droplets and channels. A model is proposed to describe this process and validate the physical interpretation of the experiments through numerical simulation. Knowing the status of the preparation, the intriguing observations in the partially melted region of the Al-1.5 wt% Ni alloys solidified in the Advanced Gradient Heating Facility of European Space Agency during the LMS and STS-95 space missions can now be explained. Finally, the influence of initial interface morphology and melt segregation on directional-solidification transient is discussed, based on a comparison of Al-Ni alloys with hypoeutectic Al-Li alloys previously grown on Earth and in space. It follows that for experiments achieved on original rods with equiaxed microstructure, the efficiency of the preparatory melting and stabilisation phases can be evaluated from the solute macrosegregation profile in the region in between the non-melted solid and directional solidification. The major conclusion is that when the melt is mixed by fluid flow, the initial conditions are near to their asymptotic state at the end of TGZM whereas, when solute diffusion is the mode of transport into the bulk liquid, the condition of homogeneous melt becomes limiting and too much time-consuming to be fulfilled, which in particular holds for the 3D-experiments carried out in the reduced-gravity environment of space.

  13. Subpixel Registration Directly from the Phase Difference

    Balci Murat


    Full Text Available This paper proposes a new approach to subpixel registration, under local/global shifts or rotation, using the phase-difference matrix. We establish the exact relationship between the continuous and the discrete phase difference of two shifted images and show that their discrete phase difference is a 2-dimensional sawtooth signal. As a result, the exact shifts or rotations can be determined to subpixel or subangle accuracy by counting the number of cycles of the phase-difference matrix along the frequency axes. The subpixel portion is represented by a fraction of a cycle corresponding to the noninteger part of the shift or rotation. The rotation angle is estimated by applying our method using a polar coordinate system. The problem is formulated as an overdetermined system of equations and is solved by imposing a regularity constraint. The tradeoff for imposing the constraint is determined by exploiting the rank constraint leading to a closed-form expression for the optimal regularization parameter.

  14. Solid Phase Characterization of Tank 241-C-108 Residual Waste Solids Samples

    Cooke, Gary A.; Pestovich, John A.; Huber, Heinz J.


    This report presents the results for solid phase characterization (SPC) of solid samples removed from tank 241-C-108 (C-108) on August 12-13,2012, using the off-riser sampler. Samples were received at the 222-S Laboratory on August 13 and were described and photographed. The SPC analyses that were performed include scanning electron microscopy (SEM) using the ASPEX(R)l scanning electron microscope, X-ray diffraction (XRD) using the Rigaku(R) 2 MiniFlex X-ray diffractometer, and polarized light microscopy (PLM) using the Nikon(R) 3 Eclipse Pol optical microscope. The SEM is equipped with an energy dispersive X-ray spectrometer (EDS) to provide chemical information. Gary A. Cooke conducted the SEM analysis, John A. Pestovich performed the XRD analysis, and Dr. Heinz J. Huber performed the PLM examination. The results of these analyses are presented here.

  15. Formation of a two-phase microstructure in Fe-Cr-Ni alloy during directional solidification

    Fu, J. W.; Yang, Y. S.; Guo, J. J.; Ma, J. C.; Tong, W. H.


    The formation and evolution of a two-phase coupled growth microstructure in AISI 304 stainless steel are investigated using a quenching method during directional solidification. It is found that the two-phase microstructure, which is composed of coupled growth of thin lathy delta ferrite (δ) and austenite (γ), forms from the melt first during solidification. As solidification proceeds, the retained liquid transforms into austenite directly. On cooling, the subsequent incomplete solid-state transformation from ferrite to austenite results in the disappearance of the thinner lathy delta ferrite, and the final two-phase coupled growth microstructure is formed. The formation mechanism of the two-phase coupled growth microstructure is analyzed theoretically based on the nucleation and constitutional undercooling (NCU) criterion. Transmission electron microscope (TEM) and EDS analyses were carried out to identify the phases and determine the phase composition, respectively.

  16. Hyperdoping silicon with selenium: solid vs. liquid phase epitaxy.

    Zhou, Shengqiang; Liu, Fang; Prucnal, S; Gao, Kun; Khalid, M; Baehtz, C; Posselt, M; Skorupa, W; Helm, M


    Chalcogen-hyperdoped silicon shows potential applications in silicon-based infrared photodetectors and intermediate band solar cells. Due to the low solid solubility limits of chalcogen elements in silicon, these materials were previously realized by femtosecond or nanosecond laser annealing of implanted silicon or bare silicon in certain background gases. The high energy density deposited on the silicon surface leads to a liquid phase and the fast recrystallization velocity allows trapping of chalcogen into the silicon matrix. However, this method encounters the problem of surface segregation. In this paper, we propose a solid phase processing by flash-lamp annealing in the millisecond range, which is in between the conventional rapid thermal annealing and pulsed laser annealing. Flash lamp annealed selenium-implanted silicon shows a substitutional fraction of ~ 70% with an implanted concentration up to 2.3%. The resistivity is lower and the carrier mobility is higher than those of nanosecond pulsed laser annealed samples. Our results show that flash-lamp annealing is superior to laser annealing in preventing surface segregation and in allowing scalability.

  17. Solid-Phase Purification of Synthetic DNA Sequences.

    Grajkowski, Andrzej; Cieslak, Jacek; Beaucage, Serge L


    Although high-throughput methods for solid-phase synthesis of DNA sequences are currently available for synthetic biology applications and technologies for large-scale production of nucleic acid-based drugs have been exploited for various therapeutic indications, little has been done to develop high-throughput procedures for the purification of synthetic nucleic acid sequences. An efficient process for purification of phosphorothioate and native DNA sequences is described herein. This process consists of functionalizing commercial aminopropylated silica gel with aminooxyalkyl functions to enable capture of DNA sequences carrying a 5'-siloxyl ether linker with a "keto" function through an oximation reaction. Deoxyribonucleoside phosphoramidites functionalized with the 5'-siloxyl ether linker were prepared in yields of 75-83% and incorporated last into the solid-phase assembly of DNA sequences. Capture of nucleobase- and phosphate-deprotected DNA sequences released from the synthesis support is demonstrated to proceed near quantitatively. After shorter than full-length DNA sequences were washed from the capture support, the purified DNA sequences were released from this support upon treatment with tetra-n-butylammonium fluoride in dry DMSO. The purity of released DNA sequences exceeds 98%. The scalability and high-throughput features of the purification process are demonstrated without sacrificing purity of the DNA sequences.

  18. Total enthalpy-based lattice Boltzmann method with adaptive mesh refinement for solid-liquid phase change

    Huang, Rongzong; Wu, Huiying


    A total enthalpy-based lattice Boltzmann (LB) method with adaptive mesh refinement (AMR) is developed in this paper to efficiently simulate solid-liquid phase change problem where variables vary significantly near the phase interface and thus finer grid is required. For the total enthalpy-based LB method, the velocity field is solved by an incompressible LB model with multiple-relaxation-time (MRT) collision scheme, and the temperature field is solved by a total enthalpy-based MRT LB model with the phase interface effects considered and the deviation term eliminated. With a kinetic assumption that the density distribution function for solid phase is at equilibrium state, a volumetric LB scheme is proposed to accurately realize the nonslip velocity condition on the diffusive phase interface and in the solid phase. As compared with the previous schemes, this scheme can avoid nonphysical flow in the solid phase. As for the AMR approach, it is developed based on multiblock grids. An indicator function is introduced to control the adaptive generation of multiblock grids, which can guarantee the existence of overlap area between adjacent blocks for information exchange. Since MRT collision schemes are used, the information exchange is directly carried out in the moment space. Numerical tests are firstly performed to validate the strict satisfaction of the nonslip velocity condition, and then melting problems in a square cavity with different Prandtl numbers and Rayleigh numbers are simulated, which demonstrate that the present method can handle solid-liquid phase change problem with high efficiency and accuracy.

  19. The role of solid-solid phase transitions in mantle convection

    Faccenda, Manuele; Dal Zilio, Luca


    With changing pressure and temperature conditions, downwelling and upwelling crustal and mantle rocks experience several solid-solid phase transitions that affect the mineral physical properties owing to structural changes in the crystal lattice and to the absorption or release of latent heat. Variations in density, together with phase boundary deflections related to the non-null reaction slope, generate important buoyancy forces that add to those induced by thermal perturbations. These buoyancy forces are proportional to the density contrast between reactant and product phases, their volume fraction, the slope and the sharpness of the reaction, and affect the style of mantle convection depending on the system composition. In a homogeneous pyrolitic mantle there is little tendency for layered convection, with slabs that may stagnate in the transition zone because of the positive buoyancy caused by post-spinel and post-ilmenite reactions, and hot plumes that are accelerated by phase transformations in the 600-800 km depth range. By adding chemical and mineralogical heterogeneities as on Earth, phase transitions introduce bulk rock and volatiles filtering effects that generate a compositional gradient throughout the entire mantle, with levels that are enriched or depleted in one or more of these components. Phase transitions often lead to mechanical softening or hardening that can be related to a different intrinsic mechanical behaviour and volatile solubility of the product phases, the heating or cooling associated with latent heat, and the transient grain size reduction in downwelling cold material. Strong variations in viscosity would enhance layered mantle convection, causing slab stagnation and plume ponding. At low temperatures and relatively dry conditions, reactions are delayed due to the sluggish kinetics, so that non-equilibrium phase aggregates can persist metastably beyond the equilibrium phase boundary. Survival of low-density metastable olivine

  20. Studies of phase transitions in the aripiprazole solid dosage form.

    Łaszcz, Marta; Witkowska, Anna


    Studies of the phase transitions in an active substance contained in a solid dosage form are very complicated but essential, especially if an active substance is classified as a BCS Class IV drug. The purpose of this work was the development of sensitive methods for the detection of the phase transitions in the aripiprazole tablets containing initially its form III. Aripiprazole exhibits polymorphism and pseudopolymorphism. Powder diffraction, Raman spectroscopy and differential scanning calorimetry methods were developed for the detection of the polymorphic transition between forms III and I as well as the phase transition of form III into aripiprazole monohydrate in tablets. The study involved the initial 10 mg and 30 mg tablets, as well as those stored in Al/Al blisters, a triplex blister pack and HDPE bottles (with and without desiccant) under accelerated and long term conditions. The polymorphic transition was not observed in the initial and stored tablets but it was visible on the DSC curve of the Abilify(®) 10 mg reference tablets. The formation of the monohydrate was observed in the diffractograms and Raman spectra in the tablets stored under accelerated conditions. The monohydrate phase was not detected in the tablets stored in the Al/Al blisters under long term conditions. The results showed that the Al/Al blisters can be recommended as the packaging of the aripiprazole tablets containing form III.

  1. Immiscible phase incorporation during directional solidification of hypermonotectics

    Andrews, J. Barry; Merrick, Roger A.


    Solidification processes in immiscible samples were investigated by directly observing the events taking place at the solid-liquid interface during directional solidification. Visualization of these events was made possible through the use of a transparent metal analog system and a temperature gradient stage assembly fitted to an optical microscope. The immiscible transparent analog system utilized was the succinonitrile-glycerol system. This system has been shown to exhibit the same morphological transitions as observed in metallic alloys of monotectic composition. Both monotectic and hypermonotectic composition samples were directionally solidified in order to gain an improved understanding of the manner in which the excess hypermonotectic liquid is incorporated into the solidifying structure. The processing conditions utilized prevented sedimentation of the excess hypermonotectic liquid by directionally solidifying the samples in very thin (13 microns), horizontally oriented cells. High thermal gradient to growth rate ratios (G/R) were used in an effort to prevent constitutional supercooling and the subsequent formation of L(sub 2) droplets in advance of the solidification front during the growth of fibrous composite structures. Results demonstrated that hypermonotectic composites could be produced in samples up to two weight percent off of the monotectic composition by using a G/R ratio greater than or equal to 4.6 x 10(exp 4) C(s)/mm(sup 2) to avoid constitutional supercooling. For hypermonotectic samples processed with G/R ratios below 4.6 x 10(exp 4) C(s)/mm(sup 2), constitutional supercooling occurred and resulted in slight interfacial instability. For these samples, two methods of incorporation of the hypermonotectic liquid were observed and are reported. The correlation between the phase spacing, lambda, and the growth rate, R, was examined and was found to obey a relationship generally associated with a diffusion controlled coupled growth process. For

  2. Critical Regimes of Two-Phase Flows with a Polydisperse Solid Phase

    Barsky, Eugene


    This book brings to light peculiarities of the formation of critical regimes of two-phase flows with a polydisperse solid phase. A definition of entropy is formulated on the basis of statistical analysis of these peculiarities. The physical meaning of entropy and its correlation with other parameters determining two-phase flows are clearly defined. The interrelations and main differences between this entropy and the thermodynamic one are revealed. The main regularities of two-phase flows both in critical and in other regimes are established using the notion of entropy. This parameter serves as a basis for a deeper insight into the physics of the process and for the development of exhaustive techniques of mass exchange estimation in such flows. The book is intended for graduate and postgraduate students of engineering studying two-phase flows, and to scientists and engineers engaged in specific problems of such fields as chemical technology, mineral dressing, modern ceramics, microelectronics, pharmacology, po...

  3. HLA antibody detection with solid phase assays: great expectations or expectations too great?

    Gebel, H M; Bray, R A


    Alloantibodies directed against HLA antigens, are a barrier to long-term solid organ allograft survival. The clinical impact of preformed, donor-directed HLA alloantibodies range from acceptable risk to unequivocal contraindication for organ transplantation. HLA antibodies are key factors that limit patient access to donor organs. Serological methods were once the only approach to identify HLA antigens and antibodies. Limitations in these technologies led to the development of solid phase approaches. In the early 1990s, the development of the polymerase chain reaction enabled DNA-based HLA antigen testing to be performed. By the mid-1990s, microparticle-based technology that utilized flow cytometry for analysis was developed to detect both classes I and II HLA antibodies. These methodologies revolutionized clinical histocompatibility testing. The strengths and weaknesses of these assays are described in detail in this review.

  4. Density functional theory study of phase IV of solid hydrogen

    Pickard, Chris J.; Martinez-Canales, Miguel; Needs, Richard J.


    We have studied solid hydrogen up to pressures of 300 GPa and temperatures of 350 K using density functional theory methods and have found “mixed structures” that are more stable than those predicted earlier. Mixed structures consist of alternate layers of strongly bonded molecules and weakly bonded graphene-like sheets. Quasiharmonic vibrational calculations show that mixed structures are the most stable at room temperature over the pressure range 250-295 GPa. These structures are stabilized with respect to strongly bonded molecular phases at room temperature by the presence of lower frequency vibrational modes arising from the graphene-like sheets. Our results for the mixed structures are consistent with the experimental Raman data [M. I. Eremets and I. A. Troyan, Nat. Mater.1476-112210.1038/nmat3175 10, 927 (2011) and R. T. Howie , Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.108.125501 108, 125501 (2012)]. We find that mixed phases are reasonable structural models for phase IV of hydrogen.

  5. Vapour phase synthesis of salol over solid acids via transesterification

    S Z Mohamed Shamshuddin; N Nagaraju


    The transesterification of methyl salicylate with phenol has been studied in vapour phase over solid acid catalysts such as ZrO2, MoO3 and SO$^{2-}_{4}$ or Mo(VI) ions modified zirconia. The catalytic materials were prepared and characterized for their total surface acidity, BET surface area and powder XRD patterns. The effect of mole-ratio of the reactants, catalyst bed temperature, catalyst weight, flowrate of reactants, WHSV and time-on-stream on the conversion (%) of phenol and selectivity (%) of salol has been investigated. A good yield (up to 70%) of salol with 90% selectivity was observed when the reactions were carried out at a catalyst bed temperature of 200°C and flow-rate of 10 mL/h in presence of Mo(VI)/ZrO2 as catalyst. The results have been interpreted based on the variation of acidic properties and powder XRD phases of zirconia on incorporation of SO$^{2-}_{4}$ or Mo(VI) ions. The effect of poisoning of acid sites of SO$^{2-}_{4}$ or Mo(VI) ions modified zirconia on total surface acidity, powder XRD phases and catalytic activity was also studied. Possible reaction mechanisms for the formation of salol and diphenyl ether over acid sites are proposed.

  6. Direct observation of ionic structure at solid-liquid interfaces

    Siretanu, Igor; Ebeling, Daniel; Andersson, Martin Peter;


    The distribution of ions and charge at solid-water interfaces plays an essential role in a wide range of processes in biology, geology and technology. While theoretical models of the solid-electrolyte interface date back to the early 20th century, a detailed picture of the structure of the electr...

  7. Phase composition, structure and properties of (ZrO2)1-x-y(Sc2O3)x(Y2O3)y solid solution crystals (x=0.08-0.11; y=0.01-0.02) grown by directional crystallization of the melt

    Borik, M. A.; Bredikhin, S. I.; Bublik, V. T.; Kulebyakin, A. V.; Kuritsyna, I. E.; Lomonova, E. E.; Milovich, F. O.; Myzina, V. A.; Osiko, V. V.; Ryabochkina, P. A.; Seryakov, S. V.; Tabachkova, N. Yu.


    For the first time crystals of the (ZrO2)1-x-y(Sc2O3)x(Y2O3)y solid solutions (x=0.08-0.11; y=0.01-0.02) have been grown by directional melt crystallization. We have determined the range of melt compositions for which growth from the melt produces of the (ZrO2)1-x-y(Sc2O3)x(Y2O3)y solid solution single crystals. The single-phase optically transparent single crystals following composition were grown: (ZrO2)0.9(Sc2O3)0.08(Y2O3)0.02; (ZrO2)0.89(Sc2O3)0.09(Y2O3)0.02; (ZrO2)0.89(Sc2O3)0.10(Y2O3)0.01; (ZrO2)0.88(Sc2O3)0.10(Y2O3)0.02. Comprehensive study of the crystal structure by using XRD, transmission electron microscopy, and Raman spectroscopy revealed that the all single crystals, which is identified by XRD data as cubic one, in fact have t″ tetragonal structure, which forms by small displacement of oxygen ions along the c-axis. Data on the phase stability of the crystals during mechanical crushing were obtained. The electrical conductivity was measured as a function of temperature by electrochemical impedance spectroscopy. It is established that (ZrO2)0.89(Sc2O3)0.10(Y2O3)0.01 crystals have the highest conductivity (0.168 S/cm at 1173 K).

  8. Applications of Liquid-Phase Microextraction in the Sample Preparation of Environmental Solid Samples

    Helena Prosen


    Full Text Available Solvent extraction remains one of the fundamental sample preparation techniques in the analysis of environmental solid samples, but organic solvents are toxic and environmentally harmful, therefore one of the possible greening directions is its miniaturization. The present review covers the relevant research from the field of application of microextraction to the sample preparation of environmental solid samples (soil, sediments, sewage sludge, dust etc. published in the last decade. Several innovative liquid-phase microextraction (LPME techniques that have emerged recently have also been applied as an aid in sample preparation of these samples: single-drop microextraction (SDME, hollow fiber-liquid phase microextraction (HF-LPME, dispersive liquid-liquid microextraction (DLLME. Besides the common organic solvents, surfactants and ionic liquids are also used. However, these techniques have to be combined with another technique to release the analytes from the solid sample into an aqueous solution. In the present review, the published methods were categorized into three groups: LPME in combination with a conventional solvent extraction; LPME in combination with an environmentally friendly extraction; LPME without previous extraction. The applicability of these approaches to the sample preparation for the determination of pollutants in solid environmental samples is discussed, with emphasis on their strengths, weak points and environmental impact.

  9. Nanoscale doping of compound semiconductors by solid phase dopant diffusion

    Ahn, Jaehyun, E-mail:; Koh, Donghyi; Roy, Anupam; Banerjee, Sanjay K., E-mail: [Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, Texas 78712 (United States); Chou, Harry [Materials Science and Engineering Program, University of Texas at Austin, Austin, Texas 78712 (United States); Kim, Taegon [Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, Texas 78712 (United States); Semiconductor R& D Center, Samsung Electronics Corporation, 1 Samsungjeonja-ro, Hwasung, Kyounggi 445-330 (Korea, Republic of); Song, Jonghan [Advanced Analysis Center, Korea Institute of Science and Technology, Cheongryang, P.O. Box 131, Seoul 130-650 (Korea, Republic of)


    Achieving damage-free, uniform, abrupt, ultra-shallow junctions while simultaneously controlling the doping concentration on the nanoscale is an ongoing challenge to the scaling down of electronic device dimensions. Here, we demonstrate a simple method of effectively doping ΙΙΙ-V compound semiconductors, specifically InGaAs, by a solid phase doping source. This method is based on the in-diffusion of oxygen and/or silicon from a deposited non-stoichiometric silicon dioxide (SiO{sub x}) film on InGaAs, which then acts as donors upon activation by annealing. The dopant profile and concentration can be controlled by the deposited film thickness and thermal annealing parameters, giving active carrier concentration of 1.4 × 10{sup 18 }cm{sup −3}. Our results also indicate that conventional silicon based processes must be carefully reviewed for compound semiconductor device fabrication to prevent unintended doping.

  10. A rapid easy—to—perform solid phase digoxin radioimmunoassay

    LiBin; ZhouMei-Ying; 等


    A solid-phase-radioimmunoassay(SPRIA) for the monitoring of blood digoxin level has been developed,in which a secondary antibody-coated polystyrene tubes are used.This noval method seems to be simple to use and only takes about an half hour.The standard curve is linear from 0.25to 4μg/L.The sensitivity of the detection is 0.1μg/L.Reproducibility studies with 3 control sera of 0.5-2.5μg/L give intraassay CV<5% and interassay CV<10%.The specimens are measured and compared with those of the conventional radioimmunoassay and the values are well correlated(r=0.96,Y=1.022X+0.04μg/L)。

  11. Solid-phase synthesis of siRNA oligonucleotides.

    Beaucage, Serge L


    Since the discovery of RNA interference (RNAi) as a means to silence the expression of specific genes, small interfering RNA (siRNA) oligonucleotides have been recognized as powerful tools for targeting therapeutically important mRNAs and eliciting their destruction. This discovery has created a high demand for synthetic oligoribonucleotides as potential therapeutics and has spurred a renaissance in the development of rapid, efficient methods for solid-phase RNA synthesis. The design and implementation of 2'-hydroxyl protecting groups that provide ribonucleoside phosphoramidites with coupling kinetics and coupling efficiencies comparable to those of deoxyribonucleoside phosphoramidites are key to the production of RNA oligonucleotides in sufficient quantity and purity for pharmaceutical applications. In this context, various siRNAs were chemically modified to identify the biophysical and biochemical parameters necessary for effective and stable RNAi-mediated gene-silencing activities.

  12. Fragment-based solid-phase assembly of oligonucleotide conjugates with peptide and polyethylene glycol ligands.

    Dirin, Mehrdad; Urban, Ernst; Noe, Christian R; Winkler, Johannes


    Ligand conjugation to oligonucleotides is an attractive strategy for enhancing the therapeutic potential of antisense and siRNA agents by inferring properties such as improved cellular uptake or better pharmacokinetic properties. Disulfide linkages enable dissociation of ligands and oligonucleotides in reducing environments found in endosomal compartments after cellular uptake. Solution-phase fragment coupling procedures for producing oligonucleotide conjugates are often tedious, produce moderate yields and reaction byproducts are frequently difficult to remove. We have developed an improved method for solid-phase coupling of ligands to oligonucleotides via disulfides directly after solid-phase synthesis. A 2'-thiol introduced using a modified nucleotide building block was orthogonally deprotected on the controlled pore glass solid support with N-butylphosphine. Oligolysine peptides and a short monodisperse ethylene glycol chain were successfully coupled to the deprotected thiol. Cleavage from the resin and full removal of oligonucleotide protection groups were achieved using methanolic ammonia. After standard desalting, and without further purification, homogenous conjugates were obtained as demonstrated by HPLC, gel electrophoresis, and mass spectrometry. The attachment of both amphiphilic and cationic ligands proves the versatility of the conjugation procedure. An antisense oligonucleotide conjugate with hexalysine showed pronounced gene silencing in a cell culture tumor model in the absence of a transfection reagent and the corresponding ethylene glycol conjugate resulted in down regulation of the target gene to nearly 50% after naked application. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  13. New methods and materials for solid phase extraction and high performance liquid chromatography

    Dumont, Philip John [Iowa State Univ., Ames, IA (United States)


    This paper describes methods for solid phase extraction and high performance liquid chromatography (HPLC). The following are described: Effects of Resin Sulfonation on the Retention of Polar Organic Compounds in Solid Phase Extraction; Ion-Chromatographic Separation of Alkali Metals In Non-Aqueous Solvents; Cation-Exchange Chromatography in Non-Aqueous Solvents; and Silicalite As a Stationary Phase For HPLC.

  14. Comparative solution and solid-phase glycosylations toward a disaccharide library

    Agoston, K.; Kröger, Lars; Agoston, Agnes


    A comparative study on solution-phase and solid-phase oligosaccharide synthesis was performed. A 16-member library containing all regioisomers of Glc-Glc, Glc-Gal, Gal-Glc, and Gal-Gal disaccharides was synthesized both in solution and on solid phase. The various reaction conditions for different...

  15. Steady-state diffusion regime in solid-phase micro extraction kinetics

    Benhabib, K.; Laak, ter T.L.; Leeuwen, van H.P.


    The temporal evolution of diffusion-controlled analyte accumulation in solid-phase microextraction (SPME) is critically discussed in terms of the various aspects of steady-state diffusion in the two phases under conditions of fast exchange of the analyte at the solid phase film/water interface. For

  16. Solid-Phase Organic Chemistry: Synthesis of 2β-(HeterocyclylthiomethylPenam Derivatives on Solid Support

    Ernesto G. Mata


    Full Text Available The synthesis of 2β-(heterocyclylthiomethylpenam derivatives on solid support has been developed. Compounds are obtained in good to high yields (based on loading of the original resin. The key step is the solid-phase double rearrangement of the corresponding penicillin sulfoxide.

  17. Development of novel solid-phase protein formulations

    Montalvo Ortiz, Brenda Liz

    Proteins are the next-generation drugs for the treatment of several diseases. However, the number of protein drugs is still limited due to the physical or chemical instability of proteins during processing, formulation, storage, and delivery. The formulation of proteins at the solid state has advantages over liquid state, such as improved stability during long-term storage and delivery and decreases transportation costs. In this dissertation, we developed new solid-phase protein formulations in which the integrity of the protein was not compromised. The long term goal of this research was to use these protein formulations to improve protein stability in drug delivery devices, such as poly(lactic-co-glycolic) acid (PLGA). The first solid-phase protein formulation developed in this investigation was named "glassification". We proposed glassification as an alternative protein dehydration technique to the common used one, lyophilization, because this last method involves a series of steps which are detrimental to protein structure and stability. The glassification method consisted on protein dehydration by the use of organic solvents. As a result of the glassification process a small (micrometer size range) protein solid bead was obtained. The proteins used to study the glassification process were lysozyme (LYS), alpha-chymotrypsin (CHYMO) and horseradish peroxidase (HRP). These studies revealed that the glassification process itself did not alter protein structure and the activity was preserved. Ethyl acetate was the most effective organic solvent for protein glassification because it led to the highest protein residual activity, no insoluble aggregate formation and is a relatively non-toxic solvent, which allow the incorporation of these protein microparticles in PLGA microspheres. The incorporation of spherical HRP microparticles into PLGA microspheres resulted in superior properties when compared with encapsulated lyophilized HRP powder, such as improved release

  18. Development of direct hydrocarbon solid oxide fuel cells

    McIntosh, Steven

    The focus of this dissertation is the development of a Solid Oxide Fuel Cell (SOFC) that can operate with hydrocarbon fuels without the need for pre-reforming. The design of an active SOFC anode requires the consideration of a number of factors including the catalytic activity of the electrode towards fuel oxidation and electronic conductivity. This work focuses on a novel system for anode fabrication that allows the catalytically active and electronically conducting components of the anode to be easily varied. The catalytic properties of the SOFC anode were examined and a strong link between SOFC performance and oxidation activity demonstrated. Of the rare-earth catalysts investigated ceria was found to have the highest activity leading to the highest fuel cell power density. This activity was further improved, especially for methane fuel, by doping with a precious metal. Furthermore, it was shown that the catalyst not only increased the rate of reaction but increased the cell Open-Circuit Voltage (OCV) suggesting a change in mechanism that increased the cell efficiency. The necessity for high electronic conductivity and connectivity in the electrode was elucidated by studying the impact of anode copper content on cell performance. Low copper loading led to reduced cell performance due to a lack of conductive pathways from the active electrode region to the external circuit. It was observed that additional conductivity was provided by a thermally deposited carbonaceous phase formed upon exposure to hydrocarbon fuels. The electrochemical characterization of SOFC electrodes is a non-trivial problem. Literature reports on the properties of similar electrodes are inconsistent and often contradictory. Using a combined experimental and theoretical approach, significant problems were found with common experimental procedures used to separate the losses associated the cell cathode from those of the anode. By calculating the effect of test geometry on this separation, it

  19. Phase diagrams and kinetics of solid-liquid phase transitions in crystalline polymer blends

    Matkar, Rushikesh A.

    A free energy functional has been formulated based on an order parameter approach to describe the competition between liquid-liquid phase separation and solid-liquid phase separation. In the free energy description, the assumption of complete solvent rejection from the crystalline phase that is inherent in the Flory diluent theory was removed as solvent has been found to reside in the crystalline phase in the form of intercalates. Using this approach, we have calculated various phase diagrams in binary blends of crystalline and amorphous polymers that show upper or lower critical solution temperature. Also, the discrepancy in the chi values obtained from different experimental methods reported in the literature for the polymer blend of poly(vinylidenefluoride) and poly(methylmethacrylate) has been discussed in the context of the present model. Experimental phase diagram for the polymer blend of poly(caprolactone) and polystyrene has also been calculated. Of particular importance is that the crystalline phase concentration as a function of temperature has been calculated using free energy minimization methods instead of assuming it to be pure. In the limit of complete immiscibility of the solvent in the crystalline phase, the Flory diluent theory is recovered. The model is extended to binary crystalline blends and the formation of eutectic, peritectic and azeotrope phase diagrams has been explained on the basis of departure from ideal solid solution behavior. Experimental eutectic phase diagram from literature of a binary blend of crystalline polymer poly(caprolactone) and trioxane were recalculated using the aforementioned approach. Furthermore, simulations on the spatio temporal dynamics of crystallization in blends of crystalline and amorphous polymers were carried out using the Ginzburg-Landau approach. These simulations have provided insight into the distribution of the amorphous polymer in the blends during the crystallization process. The simulated results

  20. Ultra-directional source of longitudinal acoustic waves based on a two-dimensional solid/solid phononic crystal

    Morvan, B.; Tinel, A.; Sainidou, R.; Rembert, P. [Laboratoire Ondes et Milieux Complexes, UMR CNRS 6294, Université du Havre, 75 rue Bellot, 76058 Le Havre (France); Vasseur, J. O.; Hladky-Hennion, A.-C. [Institut d' Electronique, de Micro-électronique et de Nanotechnologie, UMR CNRS 8520, Cité Scientifique, 59652 Villeneuve d' Ascq Cedex (France); Swinteck, N.; Deymier, P. A. [Department of Materials Science and Engineering, University of Arizona, Tucson, Arizona 85721 (United States)


    Phononic crystals (PC) can be used to control the dispersion properties of acoustic waves, which are essential to direct their propagation. We use a PC-based two-dimensional solid/solid composite to demonstrate experimentally and theoretically the spatial filtering of a monochromatic non-directional wave source and its emission in a surrounding water medium as an ultra-directional beam with narrow angular distribution. The phenomenon relies on square-shaped equifrequency contours (EFC) enabling self-collimation of acoustic waves within the phononic crystal. Additionally, the angular width of collimated beams is controlled via the EFC size-shrinking when increasing frequency.

  1. Temperature Effects on the Wind Direction Measurement of 2D Solid Thermal Wind Sensors

    Chen, Bei; Zhu, Yan-Qing; Yi, Zhenxiang; Qin, Ming; Huang, Qing-An


    For a two-dimensional solid silicon thermal wind sensor with symmetrical structure, the wind speed and direction information can be derived from the output voltages in two orthogonal directions, i.e...

  2. Immunochemical cross-reactivity between albumin and solid-phase adsorbed histamine

    Poulsen, L K; Nolte, H; Søndergaard, I


    For production of an antibody against histamine, this was coupled to human serum albumin (HSA) and used for immunization of rabbits. To test the antiserum, an immunoradiometric assay was developed comprising solid-phase bound histamine, antisera and radiolabelled protein A. Titration and inhibition...... experiments revealed that histamine adsorbed onto a solid-phase could bind the antiserum. However, neither free histamine nor histamine coupled to unrelated carriers could inhibit the binding of antiserum to the solid-phase histamine. Cross-reactivity was demonstrated between HSA and solid-phase bound...

  3. Direct Electrolytic Reduction of Solid Ta2O5 to Ta with SOM Process

    Chen, Chaoyi; Yang, Xiaqiong; Li, Junqi; Lu, Xionggang; Yang, Shufeng


    A process that uses the solid-oxide-oxygen-ion conducting membrane has been investigated to produce tantalum directly from solid Ta2O5 in molten CaCl2 or a molten mixture of 55.5MgF2-44.5CaF2 (in wt pct). The sintered porous Ta2O5 pellet was employed as the cathode, while the liquid copper alloy, saturated with graphite powder and encased in a one-end-closed yttria-stabilized-zirconia (YSZ) tube, acted as the anode. The electrolysis potential in this method is higher than that of the Fray-Farthing-Chen Cambridge process because the YSZ membrane tube blocks the melts to electrolyze, and only Ta2O5 is will be electrolyzed. The microstructures of reduced pellets and a cyclic voltammogram of solid Ta2O5 in molten CaCl2 were analyzed. In addition, the influence of particle size and porosity of the cathode pellets on metal-oxide-electrolyte, three-phase interlines was also discussed. The results demonstrate that the sintering temperature of cathode pellets and electrolytic temperature play important roles in the electrochemical process. Furthermore, this process can be used to produce Ta metal efficiently without the expensive cost of pre-electrolysis and generation of harmful by-products.

  4. Size Dependence of a Temperature-Induced Solid-Solid Phase Transition in Copper(I) Sulfide

    Rivest, Jessy B; Fong, Lam-Kiu; Jain, Prashant K; Toney, Michael F; Alivisatos, A Paul


    Determination of the phase diagrams for the nanocrystalline forms of materials is crucial for our understanding of nanostructures and the design of functional materials using nanoscale building blocks. The ability to study such transformations in nanomaterials with controlled shape offers further insight into transition mechanisms and the influence of particular facets. Here we present an investigation of the size-dependent, temperature-induced solid-solid phase transition in copper sulfide nanorods from low- to high-chalcocite. We find the transition temperature to be substantially reduced, with the high chalcocite phase appearing in the smallest nanocrystals at temperatures so low that they are typical of photovoltaic operation. Size dependence in phase trans- formations suggests the possibility of accessing morphologies that are not found in bulk solids at ambient conditions. These other- wise-inaccessible crystal phases could enable higher-performing materials in a range of applications, including sensing, switching, lighting, and photovoltaics.

  5. Phase-field modeling of microstructural pattern formation during directional solidification of peritectic alloys without morphological instability.

    Lo, T S; Karma, A; Plapp, M


    During the directional solidification of peritectic alloys, two stable solid phases (parent and peritectic) grow competitively into a metastable liquid phase of larger impurity content than either solid phase. When the parent or both solid phases are morphologically unstable, i.e., for a small temperature gradient/growth rate ratio (G/v(p)), one solid phase usually outgrows and covers the other phase, leading to a cellular-dendritic array structure closely analogous to the one formed during monophase solidification of a dilute binary alloy. In contrast, when G/v(p) is large enough for both phases to be morphologically stable, the formation of the microstructure becomes controlled by a subtle interplay between the nucleation and growth of the two solid phases. The structures that have been observed in this regime (in small samples where convection effects are suppressed) include alternate layers (bands) of the parent and peritectic phases perpendicular to the growth direction, which are formed by alternate nucleation and lateral spreading of one phase onto the other as proposed in a recent model [R. Trivedi, Metall. Mater. Trans. A 26, 1 (1995)], as well as partially filled bands (islands), where the peritectic phase does not fully cover the parent phase which grows continuously. We develop a phase-field model of peritectic solidification that incorporates nucleation processes in order to explore the formation of these structures. Simulations of this model shed light on the morphology transition from islands to bands, the dynamics of spreading of the peritectic phase on the parent phase following nucleation, which turns out to be characterized by a remarkably constant acceleration, and the types of growth morphology that one might expect to observe in large samples under purely diffusive growth conditions.

  6. Solid-phase enolate chemistry investigated using HR-MAS NMR spectroscopy.

    Fruchart, Jean-Sébastien; Lippens, Guy; Kuhn, Cyrille; Gras-Masse, Hélène; Melnyk, Oleg


    Supported P4-t-Bu enolate chemistry of phenylacetyloxymethyl polystyrene (PS) resin was investigated using high-resolution magic angle spinning (HR-MAS) NMR spectroscopy. Direct analysis of the crude reaction suspensions through the use of a diffusion filter (DF) allowed a rapid selection of the optimal experimental conditions, but also the characterization of the enolate on the solid phase. Comparison with solution experiments and literature data allowed us to address partially the structure of the enolate. HR-MAS NMR spectra of the enolate revealed also a tight interaction of P4-t-Bu base with the polymer matrix.

  7. Matrix compatible solid phase microextraction coating, a greener approach to sample preparation in vegetable matrices.

    Naccarato, Attilio; Pawliszyn, Janusz


    This work proposes the novel PDMS/DVB/PDMS fiber as a greener strategy for analysis by direct immersion solid phase microextraction (SPME) in vegetables. SPME is an established sample preparation approach that has not yet been adequately explored for food analysis in direct immersion mode due to the limitations of the available commercial coatings. The robustness and endurance of this new coating were investigated by direct immersion extractions in raw blended vegetables without any further sample preparation steps. The PDMS/DVB/PDMS coating exhibited superior features related to the capability of the external PDMS layer to protect the commercial coating, and showed improvements in terms of extraction capability and in the cleanability of the coating surface. In addition to having contributed to the recognition of the superior features of this new fiber concept before commercialization, the outcomes of this work serve to confirm advancements in the matrix compatibility of the PDMS-modified fiber, and open new prospects for the development of greener high-throughput analytical methods in food analysis using solid phase microextraction in the near future.

  8. Fixed bed reactor for solid-phase surface derivatization of superparamagnetic nanoparticles.

    Steitz, Benedikt; Salaklang, Jatuporn; Finka, Andrija; O'Neil, Conlin; Hofmann, Heinrich; Petri-Fink, Alke


    The functionalization of nanoparticles is conditio sine qua non in studies of specific interaction with a biological target. Often, their biological functionality is achieved by covalent binding of bioactive molecules on a preexisting single surface coating. The yield and quality of the resulting coated and functionalized superparamagnetic iron oxide nanoparticles (SPIONs) can be significantly improved and reaction times reduced by using solid-phase synthesis strategies. In this study, a fixed bed reactor with a quadrupole repulsive arrangement of permanent magnets was assayed for SPION surface derivatization. The magnet array around the fixed bed reactor creates very high magnetic field gradients that enables the immobilization of SPIONs with a diameter as low as 9 nm. The functionalization on the surface of immobilized 25 nm 3-(aminopropyl)trimethoxysilane-coated SPIONs (APS-SPIONs) was performed using fluorescein-isothiocyanate directly, and by the SV40 large T-antigen nuclear localization signal peptide (PKKKRKVGC) conjugated to acryloylpoly(ethylene glycol)-N-hydroxysuccinimide, where the PEG reagent is conjugated first to create a functionalized nanoparticle and the peptide is added to the acryloyl group. We show that the yield of reactant grafted on the surface of the APS-coated SPIONs was higher in solid-phase within the fixed bed reactor compared to conventional liquid-phase chemistry. In summary, the functionalization of SPIONs using a magnetically fixed bed reactor was superior to the liquid-phase reaction in terms of the yield, reaction times required for derivatization, size distribution, and scalability.

  9. Simultaneous determination of aluminium and beryllium by first-derivative synchronous solid-phase spectrofluorimetry.

    Capitán, F; Manzano, E; Navalón, A; Luis Vilchez, J; Capitán-Vallvey, L F


    A method for the simultaneous determination of aluminium and beryllium in mixtures by first-deravative synchronous solid-phase spectrofluorimetry has been developed. Aluminium and beryllium reacted with morin to give fluorescent complexes, which were fixed on a dextran-type resin. The fluoresnce of the resin, packed in a 1-mm silica cell, was measured directly with a solid-surface attachment. The constant wavelength difference chosen to optimize the determination was Deltalambda = lambda(em) = 75 nm. Aluminium was measured at lambda(em)lambda = 445/520 nm and beryllium at lambda(em)lambda(em) = 430/505 nm. The range of application is between 0.5 and 5.0 ng/ml for both aluminium and beryllium. The accuracy and precision of the method are reported. The method has been successfully applied to the determination of aluminium and beryllium in synthetic mixtures and natural waters.

  10. Vacuum-assisted headspace solid phase microextraction of polycyclic aromatic hydrocarbons in solid samples.

    Yiantzi, Evangelia; Kalogerakis, Nicolas; Psillakis, Elefteria


    For the first time, Vacuum Assisted Headspace Solid Phase Microextraction (Vac-HSSPME) is used for the recovery of polycyclic aromatic hydrocarbons (PAHs) from solid matrices. The procedure was investigated both theoretically and experimentally. According to the theory, reducing the total pressure increases the vapor flux of chemicals at the soil surface, and hence improves HSSPME extraction kinetics. Vac-HSSPME sampling could be further enhanced by adding water as a modifier and creating a slurry mixture. For these soil-water mixtures, reduced pressure conditions may increase the volatilization rates of compounds with a low K(H) present in the aqueous phase of the slurry mixture and result in a faster HSSPME extraction process. Nevertheless, analyte desorption from soil to water may become a rate-limiting step when significant depletion of the aqueous analyte concentration takes place during Vac-HSSPME. Sand samples spiked with PAHs were used as simple solid matrices and the effect of different experimental parameters was investigated (extraction temperature, modifiers and extraction time). Vac-HSSPME sampling of dry spiked sand samples provided the first experimental evidence of the positive combined effect of reduced pressure and temperature on HSSPME. Although adding 2 mL of water as a modifier improved Vac-HSSPME, humidity decreased the amount of naphthalene extracted at equilibrium as well as impaired extraction of all analytes at elevated sampling temperatures. Within short HSSPME sampling times and under mild sampling temperatures, Vac-HSSPME yielded linear calibration curves in the range of 1-400 ng g(-1) and, with the exception of fluorene, regression coefficients were found higher than 0.99. The limits of detection for spiked sand samples ranged from 0.003 to 0.233 ng g(-1) and repeatability from 4.3 to 10 %. Finally, the amount of PAHs extracted from spiked soil samples was smaller compared to spiked sand samples, confirming that soil could bind target

  11. Quantitation of drugs via molecularly imprinted polymer solid phase extraction and electrospray ionization mass spectrometry: benzodiazepines in human plasma


    The association of solid phase extraction with molecularly imprinted polymers (MIP) and electrospray ionization mass spectrometry (ESI-MS) is applied to the direct extraction and quantitation of benzodiazepines in human plasma. The target analytes are sequestered by MIP and directly analyzed by ESI-MS. Due to the MIP highly selective extraction, ionic suppression during ESI is minimized; hence no separation is necessary prior to ESI-MS, which greatly increases analytical speed. Benzodiazepine...

  12. Modeling the solid-liquid phase transition in saturated triglycerides

    Pink, David A.; Hanna, Charles B.; Sandt, Christophe; MacDonald, Adam J.; MacEachern, Ronald; Corkery, Robert; Rousseau, Dérick


    We investigated theoretically two competing published scenarios for the melting transition of the triglyceride trilaurin (TL): those of (1) Corkery et al. [Langmuir 23, 7241 (2007)], in which the average state of each TL molecule in the liquid phase is a discotic "Y" conformer whose three chains are dynamically twisted, with an average angle of ˜120° between them, and those of (2) Cebula et al. [J. Am. Oil Chem. Soc. 69, 130 (1992)], in which the liquid-state conformation of the TL molecule in the liquid phase is a nematic h∗-conformer whose three chains are in a modified "chair" conformation. We developed two competing models for the two scenarios, in which TL molecules are in a nematic compact-chair (or "h") conformation, with extended, possibly all-trans, chains at low-temperatures, and in either a Y conformation or an h∗ conformation in the liquid state at temperatures higher than the phase-transition temperature, T∗=319 K. We defined an h-Y model as a realization of the proposal of Corkery et al. [Langmuir 23, 7241 (2007)], and explored its predictions by mapping it onto an Ising model in a temperature-dependent field, performing a mean-field approximation, and calculating the transition enthalpy ΔH. We found that the most plausible realization of the h-Y model, as applied to the solid-liquid phase transition in TL, and likely to all saturated triglycerides, gave a value of ΔH in reasonable agreement with the experiment. We then defined an alternative h-h∗ model as a realization of the proposal of Cebula et al. [J. Am. Oil Chem. Soc. 69, 130 (1992)], in which the liquid phase exhibits an average symmetry breaking similar to an h conformation, but with twisted chains, to see whether it could describe the TL phase transition. The h-h∗ model gave a value of ΔH that was too small by a factor of ˜3-4. We also predicted the temperature dependence of the 1132 cm-1 Raman band for both models, and performed measurements of the ratios of three TL Raman

  13. Preparation of Pt/C Catalyst with Solid Phase Reaction Method


    The Pt/C catalyst was prepared with solid phase reaction method (Pt/C(S)) for the first time. Its performances were compared with that prepared by the traditional liquid phase reaction method. The results demonstrate that the electrocatalytic activity of Pt/C catalyst with solid phase reaction method for methanol oxidation is higher than that with liquid phase reaction method. XRD and TEM measurements indicate that the Pt/C(S) possesses low crystalline extent and small particle size.

  14. Binding of properdin to solid-phase immune complexes

    Junker, A; Baatrup, G; Svehag, S E


    The capacity of serum to support deposition of C3, properdin and factor B was studied by enzyme-linked immunosorbent assay using solid-phase immune complexes (IC) for activation of complement. Deposition of C3 and properdin occurred in fairly dilute normal human serum (NHS), but factor B uptake...... was hardly detectable. Alternative pathway-mediated deposition of C3 with slow kinetics was demonstrated in C2-deficient serum and in NHS depleted of C1q, factor D and properdin (C1qDP-depleted serum) after reconstitution with factor D and properdin. Efficient uptake of properdin required a functional...... classical pathway, in the presence of which C3 and properdin were rapidly deposited onto the IC. Judging from findings in C3-deficient serum, factor I-deficient serum, and C1qDPB-depleted serum, the uptake of properdin was strictly C3-dependent, and did not require the presence of factors B and D. Thus, C3b...

  15. Microwave heating in solid-phase peptide synthesis.

    Pedersen, Søren L; Tofteng, A Pernille; Malik, Leila; Jensen, Knud J


    The highly refined organic chemistry in solid-phase synthesis has made it the method of choice not only to assemble peptides but also small proteins - mainly on a laboratory scale but increasingly also on an industrial scale. While conductive heating occasionally has been applied to peptide synthesis, precise microwave irradiation to heat the reaction mixture during coupling and N(α)-deprotection has become increasingly popular. It has often provided dramatic reductions in synthesis times, accompanied by an increase in the crude peptide purity. Microwave heating has been proven especially relevant for sequences which might form β-sheet type structures and for sterically difficult couplings. The beneficial effect of microwave heating appears so far to be due to the precise nature of this type of heating, rather than a peptide-specific microwave effect. However, microwave heating as such is not a panacea for all difficulties in peptide syntheses and the conditions may need to be adjusted for the incorporation of Cys, His and Asp in peptides, and for the synthesis of, for example, phosphopeptides, glycopeptides, and N-methylated peptides. Here we provide a comprehensive overview of the advances in microwave heating for peptide synthesis, with a focus on systematic studies and general protocols, as well as important applications. The assembly of β-peptides, peptoids and pseudopeptides are also evaluated in this critical review (254 references).

  16. Solid-phase microextraction and the human fecal VOC metabolome.

    Emma Dixon

    Full Text Available The diagnostic potential and health implications of volatile organic compounds (VOCs present in human feces has begun to receive considerable attention. Headspace solid-phase microextraction (SPME has greatly facilitated the isolation and analysis of VOCs from human feces. Pioneering human fecal VOC metabolomic investigations have utilized a single SPME fiber type for analyte extraction and analysis. However, we hypothesized that the multifarious nature of metabolites present in human feces dictates the use of several diverse SPME fiber coatings for more comprehensive metabolomic coverage. We report here an evaluation of eight different commercially available SPME fibers, in combination with both GC-MS and GC-FID, and identify the 50/30 µm CAR-DVB-PDMS, 85 µm CAR-PDMS, 65 µm DVB-PDMS, 7 µm PDMS, and 60 µm PEG SPME fibers as a minimal set of fibers appropriate for human fecal VOC metabolomics, collectively isolating approximately 90% of the total metabolites obtained when using all eight fibers. We also evaluate the effect of extraction duration on metabolite isolation and illustrate that ex vivo enteric microbial fermentation has no effect on metabolite composition during prolonged extractions if the SPME is performed as described herein.

  17. Phase I studies of porfiromycin (NSC--56410) in solid tumors.

    Grage, T B; Weiss, A J; Wilson, W; Reynolds, V


    Porfiromycin was given to a group of patients with a variety of solid tumors. Of 114 patients admitted to the study, 103 yielded evaluable data. The following dosage schedules were used to determine the toxicity of porfiromycin when given in multiple doses by intravenous injection: 0.2 mg/kg x 5 days, 0.3 mg/kg x 5 days, 0.35 mg/kg x 5 days, 0.4 mg/kg x 5 days, 0.24 mg/kg x 10 days and 0.6 mg/kg weekly. Toxic effects noted were mainly leukopenia, thrombocytopenia, and, when injected paravenously, local tissue necrosis. Biological effects were noted at all dosage levels and were more severe at the higher dosages. The data suggest that profiromycin administered intravenously at a dose of 0.35 mg/kg daily for 5 days results in moderate hermatological toxicity and clinical evaluation in a Phase II study at this dosage level is indicated.

  18. Automated solid-phase peptide synthesis to obtain therapeutic peptides

    Veronika Mäde


    Full Text Available The great versatility and the inherent high affinities of peptides for their respective targets have led to tremendous progress for therapeutic applications in the last years. In order to increase the drugability of these frequently unstable and rapidly cleared molecules, chemical modifications are of great interest. Automated solid-phase peptide synthesis (SPPS offers a suitable technology to produce chemically engineered peptides. This review concentrates on the application of SPPS by Fmoc/t-Bu protecting-group strategy, which is most commonly used. Critical issues and suggestions for the synthesis are covered. The development of automated methods from conventional to essentially improved microwave-assisted instruments is discussed. In order to improve pharmacokinetic properties of peptides, lipidation and PEGylation are described as covalent conjugation methods, which can be applied by a combination of automated and manual synthesis approaches. The synthesis and application of SPPS is described for neuropeptide Y receptor analogs as an example for bioactive hormones. The applied strategies represent innovative and potent methods for the development of novel peptide drug candidates that can be manufactured with optimized automated synthesis technologies.

  19. Headspace solid-phase microextraction for wine volatile analysis.

    Azzi-Achkouty, Samar; Estephan, Nathalie; Ouaini, Naïm; Rutledge, Douglas N


    The most commonly used technique to prepare samples for the analysis of wine volatile is the headspace solid-phase microextraction (HS-SPME). This method has gained popularity in last few years, as it is a unique solventless preparation technique. In this paper, a summary of recently published studies using HS-SPME for the analysis of wine aromas, with special emphasis on the method developed, has been compiled. Several papers are discussed in detail, mainly with respect to the SPME conditions used. A brief summary of the reviews related to HS-SPME analysis is given and discussed. Several parameters affecting the HS-SPME, such as the salt concentration and the agitation conditions, are used in the same way as used in several papers. The HS-SPME extraction proved to be sufficiently sensitive to satisfy legislative requirements related to low detection and quantification limits as well as method accuracy and precision requirements. However, in order to achieve the best performance and precision, the protocol needs to be optimized for each case. The effect of different parameters must be well characterized to ensure correct extraction and desorption to ensure the transfer of extracted compounds into the analytical system. The operating parameters, such as time, temperature, and agitation, must then be kept constant for all the samples.

  20. Determination of trace impurities in titanium dioxide by direct solid sampling electrothermal atomic absorption spectrometry

    Docekal, Bohumil [Institute of Analytical Chemistry, Academy of Sciences of the Czech Republic, Veveri 97, CZ-61142, Brno (Czech Republic)], E-mail:; Vojtkova, Blanka [Institute of Materials Science, Faculty of Chemistry, Brno University of Technology, Purkynova 118, CZ-61200 Brno (Czech Republic)


    A true direct solid sampling electrothermal atomic absorption spectrometry method with Zeeman-effect background correction (Analytik Jena ZEEnit 60 AAS) was developed for the determination of As, Cd, Hg, Pb, Sb and Zn in powdered titanium dioxide of pharmaceutical, food and cosmetics grade. The interaction of the titanium matrix and graphite surface of the sample carrier boat in a transversely heated graphite tube atomizer was investigated. Conversion of titanium dioxide to interfering TiO{sub 2}-TiC-liquid phase, running out the sampling boat, was observed at temperatures above 2000 deg. C. The temperature program was optimized accordingly for these volatile analytes in atomization and cleaning steps in order to prevent this interference and to prolong significantly the analytical lifetime of the boat to more than one thousand runs. For all elements, calibration by aqueous standard addition method, by wet-chemically analyzed samples with different content of analytes and/or by dosing one sample in different amounts, were proved as adequate quantification procedures. Linear dynamic calibration working ranges can be considerably expanded up to two orders of magnitude within one measurement run by applying three-field dynamic mode of the Zeeman background correction system. The results obtained by true direct solid sampling technique are compared with those of other independent, mostly wet-chemical methods. Very low limits of detection (3{sigma} criterion) of true solid sampling technique of 21, 0.27, 24, 3.9, 6.3 and 0.9 ng g{sup -1} were achieved for As, Cd, Hg, Pb, Sb and Zn, respectively.

  1. Determining the solid phases hosting arsenic in Mekong Delta sediments

    Wucher, M.; Stuckey, J. W.; McCurdy, S.; Fendorf, S.


    The major river systems originating from the Himalaya deposit arsenic bearing sediment into the deltas of South and Southeast Asia. High rates of sediment and organic carbon deposition combined with frequent flooding leads to anaerobic processes that release arsenic into the pore-water. Arsenic concentrations in the groundwater of these sedimentary basins are often above the World Health Organization drinking water standard of 10 μg As L-1. As a result, 150 million people are at risk of chronic arsenic poisoning through water and rice consumption. The composition of the iron bearing phases hosting the arsenic in these deltaic sediments is poorly understood. Here we implemented a suite of selective chemical extractions to help constrain the types of arsenic bearing solid phases, which were complimented with synchrotron-based X-ray absorption spectroscopy and X-ray diffraction analyses to define the arsenic and iron mineralogy of the system. Sediment cores were collected in triplicate from a seasonally-inundated wetland in Cambodia at depths of 10, 50, 100, and 150 centimeters. We hypothesize that (i) arsenic will be predominantly associated with iron oxides, and (ii) the ratio of crystalline to amorphous iron oxides will increase with sediment depth (and age). We performed four selective extractions in parallel to quantify the various pools of arsenic. First, 1 M MgCl2 was used to extract electrostatically-bound arsenic (labile forms) from the sediment. Second, 1 M NaH2PO4 targeted strongly adsorbed arsenic. Third, 1 M HCl was used to liberated arsenic coprecipitated with amorphous Fe/Mn oxides, carbonates, and acid-volatile sulfides. Finally, a dithionite extraction was used to account for arsenic associated with reducible Fe/Mn oxides. Through this work, we identified the composition of the phases hosting arsenic at various depths through the soil profile, improving our understanding of how arsenic persists in the aquifer. In addition, defining the arsenic and

  2. An acid-stable tert-butyldiarylsilyl (TBDAS) linker for solid-phase organic synthesis.

    Diblasi, Christine M; Macks, Daniel E; Tan, Derek S


    [reaction: see text] A new, robust tert-butyldiarylsilyl (TBDAS) linker has been developed for solid-phase organic synthesis. This linker is stable to both protic and Lewis acidic reaction conditions, overcoming a significant limitation of previously reported silyl linkers. Solid-phase acetal deprotection, olefination, asymmetric allylation, and silyl protecting group deblocking reactions have been demonstrated with TBDAS-linked substrates.

  3. 40 CFR 227.32 - Liquid, suspended particulate, and solid phases of a material.


    ... MATERIALS Definitions § 227.32 Liquid, suspended particulate, and solid phases of a material. (a) For the... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Liquid, suspended particulate, and solid phases of a material. 227.32 Section 227.32 Protection of Environment ENVIRONMENTAL...


    A. R. Koohpaei ، S. J. Shahtaheri ، M. R. Ganjali ، A. Rahimi Forushani


    Full Text Available Solid phase extraction is one of the major applications of molecularly imprinted polymers fields for clean-up of environmental and biological samples namely molecularly imprinted solid-phase extraction. In this study, solid phase extraction using the imprinted polymer has been optimized with the experimental design approach for a triazine herbicide, named atrazine with regard to the critical factors which influence the molecular imprinted solid phase extraction efficiency such as sample pH, concentration, flow-rate, volume, elution solvent, washing solvent and sorbent mass. Optimization methods that involve changing one factor at a time can be laborious. A novel approach for the optimization of imprinted solid-phase extraction using chemometrics is described. The factors were evaluated statistically and also validated with spiked water samples and showed a good reproducibility over six consecutive days as well as six within-day experiments. Also, in order to the evaluate efficiency of the optimized molecularly imprinted solid-phase extraction protocols, enrichment capacity, reusability and cross-reactivity of cartridges have been also evaluated. Finally, selective molecularly imprinted solid-phase extraction of atrazine was successfully demonstrated with a recovery above 90% for spiked drinking water samples. It was concluded that the chemometrics is frequently employed for analytical method optimization and based on the obtained results, it is believed that the central composite design could prove beneficial for aiding the molecularly imprinted polymer and molecularly imprinted solid-phase extraction development.

  5. Facile synthesis of aliphatic isothiocyanates and thioureas on solid phase using peptide coupling reagents

    Boas, Ulrik; Andersen, Heidi Gertz; Christensen, Jørn B.;


    Peptide coupling reagents can be used as versatile reagents for the formation of aliphatic isothiocyanates and thioureas on solid phase from the corresponding solid-phase anchored aliphatic primary amines. The formation of the thioureas is fast and highly chemoselective, and proceeds via formation...

  6. The Iron-Iron Carbide Phase Diagram: A Practical Guide to Some Descriptive Solid State Chemistry.

    Long, Gary J.; Leighly, H. P., Jr.


    Discusses the solid state chemistry of iron and steel in terms of the iron-iron carbide phase diagram. Suggests that this is an excellent way of introducing the phase diagram (equilibrium diagram) to undergraduate students while at the same time introducing the descriptive solid state chemistry of iron and steel. (Author/JN)

  7. Complement fixation by solid phase immune complexes. Reduced capacity in SLE sera

    Baatrup, G; Jonsson, H; Sjöholm, A


    We describe an ELISA for assessment of complement function based on the capacity of serum to support fixation of complement components to solid phase immune complexes (IC). Microplates were coated with aggregated bovine serum albumin (BSA) followed by rabbit anti-BSA IgG. The solid phase IC were ...

  8. Solid-state retrodirective phased array concepts for microwave power transmission from Solar Power Satellite

    Schroeder, K. G.; Petroff, I. K.


    Two prototype solid-state phased array systems concepts for potential use in the Solar Power Satellite are described. In both concepts, the beam is centered on the rectenna by means of phase conjugation of a pilot signal emanating from the ground. Also discussed is on-going solid-state amplifier development.

  9. DNA display III. Solid-phase organic synthesis on unprotected DNA.

    David R Halpin


    Full Text Available DNA-directed synthesis represents a powerful new tool for molecular discovery. Its ultimate utility, however, hinges upon the diversity of chemical reactions that can be executed in the presence of unprotected DNA. We present a solid-phase reaction format that makes possible the use of standard organic reaction conditions and common reagents to facilitate chemical transformations on unprotected DNA supports. We demonstrate the feasibility of this strategy by comprehensively adapting solid-phase 9-fluorenylmethyoxycarbonyl-based peptide synthesis to be DNA-compatible, and we describe a set of tools for the adaptation of other chemistries. Efficient peptide coupling to DNA was observed for all 33 amino acids tested, and polypeptides as long as 12 amino acids were synthesized on DNA supports. Beyond the direct implications for synthesis of peptide-DNA conjugates, the methods described offer a general strategy for organic synthesis on unprotected DNA. Their employment can facilitate the generation of chemically diverse DNA-encoded molecular populations amenable to in vitro evolution and genetic manipulation.

  10. Solid-Phase Organic Synthesis and Catalysis: Some Recent Strategies Using Alumina, Silica, and Polyionic Resins

    Basudeb Basu; Susmita Paul


    Solid-phase organic synthesis (SPOS) and catalysis have gained impetus after the seminal discovery of Merrifield’s solid-phase peptide synthesis and also because of wide applicability in combinatorial and high throughput chemistry. A large number of organic, inorganic, or organic-inorganic hybrid materials have been employed as polymeric solid supports to promote or catalyze various organic reactions. This review article provides a concise account on our approaches involving the use of (i) al...

  11. Local Gas Phase Flow Characteristics of a Gas—Liquid—Solid Three—Phase Reversed Flow Jet Loop Reactor

    WENJianping; ChenYunlin; 等


    The local gas-phase flow characteristics such as local gas holdup (εg), local bubble velocity (Vb) and local bubble mean diameter(db) at a specified point in a gas-liquid-solid three-phase reversed flow jet loop reactor was experimentally investigated by a five-point conductivity probe. The effects of gas jet flow rate, liquid jet flow rate, solid loading, nozzle diameter and axial position on the local εg,Vb and db profiles were discussed. The presence of solids at low solid concentrations not only increased the local εg and Vb, but also decreased the local db. The optimum solid olading for the maximum local εg and Vb together with the minimum local db was 0.16×10-3m3, corresponding to a solid volume fraction,εS=2.5%.

  12. Determination of amphetamines in hair by integrating sample disruption, clean-up and solid phase derivatization.

    Argente-García, A; Moliner-Martínez, Y; Campíns-Falcó, P; Verdú-Andrés, J; Herráez-Hernández, R


    The utility of matrix solid phase dispersion (MSPD) for the direct analysis of amphetamines in hair samples has been evaluated, using liquid chromatography (LC) with fluorescence detection and precolumn derivatization. The proposed approach is based on the employment of MSPD for matrix disruption and clean-up, followed by the derivatization of the analytes onto the dispersant-sample blend. The fluorogenic reagent 9-fluorenylmethyl chloroformate (FMOC) has been used for derivatization. Different conditions for MSPD, analyte purification and solid phase derivatization have been tested, using amphetamine (AMP), methamphetamine (MET), ephedrine (EPE) and 3,4-methylenedioxymethamphetamine (MDMA) as model compounds. The results have been compared with those achieved by using ultrasound-assisted alkaline digestion and by MSPD combined with conventional solution derivatization. On the basis of the results obtained, a methodology is proposed for the analysis of amphetamines in hair which integrates sample disruption, clean-up and derivatization using a C18 phase. Improved sensitivity is achieved with respect to that obtained by the alkaline digestion or by the MSPD followed by solution derivatization methods. The method can be used for the quantification of the tested amphetamines within the 2.0-20.0ng/mg concentration interval, with limits of detection (LODs) of 0.25-0.75ng/mg. The methodology is very simple and rapid (the preparation of the sample takes less than 15min).

  13. Inhibition of a solid phase reaction among excipients that accelerates drug release from a solid dispersion with aging.

    Mizuno, Masayasu; Hirakura, Yutaka; Yamane, Ikuro; Miyanishi, Hideo; Yokota, Shoji; Hattori, Munetaka; Kajiyama, Atsushi


    Hydrophobic drug substances can be formulated as a solid dispersion or solution using macromolecular matrices with high glass transition temperatures to attain satisfactory dissolution. However, very few marketed products have previously relied on solid dispersion technology due to physical and chemical instability problems, and processing difficulties. In the present study, a modified release product of a therapeutic drug for hypertension, Barnidipine hydrochloride, was developed. The drug product consisted of solid dispersion based on a matrix of carboxymethylethylcellulose (CMEC), which was produced using the spray-coating method. An enteric coat layer was sprayed on the surface of the solid dispersion to control drug release. Interestingly, the release rate accelerated as the drug product aged, while there were no indications of deceleration of the release rate which was due to crystallization of the drug substance. To prevent changes in the dissolution kinetics during storage periods, a variety of processing conditions were tried. It was found that not only use of non-aqueous solvents but also a reduction in coating temperatures consistently resulted in stable solid dispersions. The molecular bases of dissolution of the drug substance from those matrices were investigated. The molecular weight of CMEC was found to be a dominant factor that determined dissolution kinetics, which followed zero-order release, suggesting an involvement of an osmotic pumping mechanism. While dissolution was faster using a higher molecular weight CMEC, the molecular weight of CMEC in the drug product slowly increased with aging (solid phase reaction) depending on the processing conditions, causing the time-induced elevation of dissolution. While no crystalline components were found in the solid dispersion, the amorphous structure maintained a degree of non-equilibrium by nature. Plasticization by water in the coating solution relaxed the amorphous system and facilitated phase

  14. Isolation of tetracyclines in milk using a solid-phase extracting column and water eluent.

    Furusawa, Naoto


    An isolating method using a solid-phase extraction (SPE) ISOLUTE(R) C8 endcapped syringe-column for routine monitoring of residual tetracyclines (TCs) (oxytetracycline (OTC), tetracycline (TC), chlortetracycline (CTC), and doxycycline (DC)) in cow's milk is presented. In the simplest and most environmentally harmless method, milk samples could be applied directly to the SPE column, following which all TCs were eluted with water. No organic solvents were used at all. The purified sample was injected into a high-performance liquid chromatography (HPLC) with a photo-diode array detector (PDAD). For the HPLC determination/identification, a LiChrospher(R) 100 RP-8 endcapped column and a mobile phase of acetonitrile -7% (v v(-1)) acetic acid solution (in water) (35:65, v v(-1)) with a PDAD was used. The total time required for the analysis of one sample was 80 and <5%, respectively.

  15. Multiplex Solid-Phase PCR for Rapid Detection and Identification of Salmonella spp. at Sub-species

    Cao, Cuong; Høgberg, Jonas; Wolff, Anders

    -PCR gel electrophoresis. The method will be useful for development of point-of-care devices for rapid detection and identification of Salmonella spp. A solid-phase PCR for rapid detection and identification of S. enteritidis, S. typhimurium and S. dublin is developed. The method offers advantages......This study presents a solid-phase PCR (SP-PCR) for rapid detection, identification, and sub-typing of various Salmonella species, the major food-borne cause of salmonellosis. The target DNA is firstly amplified with PCR primers (one primer is labeled with fluorophores) in the liquid phase...... by the liquid phase primer thus generating new templates for the SP-PCR. After the reaction, PCR products labeled with fluorophores remain attached to the substrate and can be visualized directly by fluorescence readout devices. Using this method, S. enteritidis, S. typhimurium and S. dublin can be detected...

  16. Pressure Effects on Solid State Phase Transformation of Aluminium Bronze in Cooling Process

    WANG Hai-Yan; CHEN Yan; LIU Yu-Wen; LI Fei; LIU Jian-Hua; PENG Gui-Rong; WANG Wen-Kui


    Effects of high pressure (6 GPa) on the solid state phase transformation kinetic parameters of aluminum bronze during the cooling process are investigated, based on the measurement and calculation of its solid state phase transformation temperature, duration and activation energy and the observation of its microstructures. The results show that high pressure treatment can reduce the solid phase transformation temperature and activation energy in the cooling process and can shorten the phase transformation duration, which is favorable when forming fine-grained aluminum bronze.

  17. The importance of screening solid-state phases of a racemic modification of a chiral drug: thermodynamic and structural characterization of solid-state phases of etiracetam.

    Herman, Christelle; Vermylen, Valérie; Norberg, Bernadette; Wouters, Johan; Leyssens, Tom


    In this contribution different solid-state forms of the racemic compound (RS)-2-(2-oxo-pyrrolidin-1yl)-butyramide are studied from a structural and thermal point of view. Three different solid-state phases were identified, including two polymorphs and one hydrate phase. Comparison is made with the structure of the (S)-enantiomer, for which only one solid-state phase is known. The basic structural motif found in both polymorphs of the racemic compound is similar, but the basic motif observed for the hydrate differs. These synthons could in principle be used in future polymorph prediction studies to screen for possible alternative forms of the enantiopure compound. Based on the structure of the hydrate, further efforts should therefore be made in order to identify a hydrate structure of the enantiopure compound. Studying the different phases of a racemic compound can therefore help to guide polymorphic screening of an enantiopure compound.

  18. Solid and liquid phase equilibria and solid-hydrate formation in binary mixtures of water with amines

    车冠全; 彭文烈; 黄良恩; 古喜兰; 车飙


    Solid and liquid phase diagrams have been constructed for {water+triethylamine,or+N,N-dimethylformamide(DMF) or+N,N-dimethlacetamide (DMA)} Solid-hydrates form with the empirical formulae N(C2H5)3 3H2O,DMF 3H2O,DMF 2H2O,DMA 3H2O and (DMA)2 3H2O.All are congruently melting except the first which melts incongruently.The solid-hydrate formation is attributed to hydrogen bond.The results are compared with the references

  19. Experimental observation of direct current voltage-induced phase synchronization

    Haihong Li; Weiqing Liu; Qiongling Dai; Jinghua Xiao


    The dynamics of two uncoupled distinct Chua circuits driven by a common direct current voltage is explored experimentally. It was found that, with increasing current intensity, the dominant frequencies of these two Chua circuits will first vary at different speeds, approach an identical value for a certain current intensity and then separate. Techniques such as synchronization index and phase difference distribution were employed to analyze the phase coherence between these two Chua circuits.

  20. Solid phase epitaxial regrowth of (100)GaAs

    Almonte, Marlene Isabel [California Univ., Berkeley, CA (United States). Dept. of Materials Science and Mineral Engineering


    This thesis showed that low temperature (250°C) SPE of stoichiometrically balanced ion implanted GaAs layers can yield good epitaxial recovery for doses near the amorphization threshold. For 250°C anneals, most of the regrowth occurred in the first 10 min. HRTEM revealed much lower stacking fault density in the co-implanted sample than in the As-only and Ga-only samples with comparable doses. After low temp annealing, the nonstoichiometric samples had a large number of residual defects. For higher dose implants, very high temperatures (700°C) were needed to remove residual defects for all samples. The stoichiometrically balanced layer did not regrow better than the Ga-only and As-only samples. The co-implanted sample exhibited a thinner amorphous layer and a room temperature (RT) annealing effect. The amorphous layer regrew about 5 nm, suggesting that stoichiometrically balanced amorphous layers can regrow even at RT. Mechanisms for solid phase crystallization in (100)GasAs is discussed: nucleation and growth of randomly oriented crystallites and SPE. These two mechanisms compete in compound semiconductors at much lower temperatures than in Si. For the low dose As-only and Ga-only samples with low-temp anneals, both mechanisms are active. For this amorphization threshold dose, crystallites remain in the amorphous layer for all as-implants. 250°C annealing showed recrystallization from the surface and bulk for these samples; for the co-implant, the mechanism is not evident.

  1. Ultrarapid mutation detection by multiplex, solid-phase chemical cleavage

    Rowley, G.; Saad, S.; Giannelli, F.; Green, P.M. [Guy`s & St. Thomas`s Hospitals, London (United Kingdom)


    The chemical cleavage of mismatches in heteroduplexes formed by probe and test DNA detects and locates any sequence change in long DNA segments ({approximately}1.8 kb), and its efficiency has been well tested in the analysis of both average (e.g., coagulation factor IX) and large, complex genes (e.g., coagulation factor VIII and dystrophin). In the latter application RT/PCR products allow the examination of all essential sequences of the gene in a minimum number of reactions. We use two specific chemical reactants (hydroxylamine and osmium tetroxide) and piperidine cleavage of the above procedure to develop a very fast mutation screening method. This is based on: (1) 5{prime} or internal fluorescent labeling to allow concurrent screening of three to four DNA fragments and (2) solid-phase chemistry to use a microliter format and reduce the time required for the procedure, from amplification of sequence to gel loading inclusive, to one person-working-day. We test the two variations of the method, one entailing 5{prime} labeling of probe DNA and the other uniform labeling of both probe and target DNA, by detecting 114 known hemophilia B (coagulation factor IX) mutations and by analyzing 129 new patients. Uniform labeling of both probe and target DNA prior to formation of the heteroduplexes leads to almost twofold redundancy in the ability to detect mutations. Alternatively, the latter procedure may offer very efficient though less than 100% screening for sequence changes with only hydroxylamine. The full method with two chemical reactions (hydroxylamine and osmium tetroxide) should allow one person to screen with virtually 100% accuracy more than 300 kb of sequence in three ABI 373 gels in 1 day. 26 refs., 7 figs., 1 tab.

  2. Porous, High Capacity Coatings for Solid Phase Microextraction by Sputtering.

    Diwan, Anubhav; Singh, Bhupinder; Roychowdhury, Tuhin; Yan, DanDan; Tedone, Laura; Nesterenko, Pavel N; Paull, Brett; Sevy, Eric T; Shellie, Robert A; Kaykhaii, Massoud; Linford, Matthew R


    We describe a new process for preparing porous solid phase microextraction (SPME) coatings by the sputtering of silicon onto silica fibers. The microstructure of these coatings is a function of the substrate geometry and mean free path of the silicon atoms, and the coating thickness is controlled by the sputtering time. Sputtered silicon structures on silica fibers were treated with piranha solution (a mixture of concd H2SO4 and 30% H2O2) to increase the concentration of silanol groups on their surfaces, and the nanostructures were silanized with octadecyldimethylmethoxysilane in the gas phase. The attachment of this hydrophobic ligand was confirmed by X-ray photoelectron spectroscopy and contact angle goniometry on model, planar silicon substrates. Sputtered silicon coatings adhered strongly to their surfaces, as they were able to pass the Scotch tape adhesion test. The extraction time and temperature for headspace extraction of mixtures of alkanes and alcohols on the sputtered fibers were optimized (5 min and 40 °C), and the extraction performances of SPME fibers with 1.0 or 2.0 μm of sputtered silicon were compared to those from a commercial 7 μm poly(dimethylsiloxane) (PDMS) fiber. For mixtures of alcohols, aldehydes, amines, and esters, the 2.0 μm sputtered silicon fiber yielded signals that were 3-9, 3-5, 2.5-4.5, and 1.5-2 times higher, respectively, than those of the commercial fiber. For the heavier alkanes (undecane-hexadecane), the 2.0 μm sputtered fiber yielded signals that were approximately 1.0-1.5 times higher than the commercial fiber. The sputtered fibers extracted low molecular weight analytes that were not detectable with the commercial fiber. The selectivity of the sputtered fibers appears to favor analytes that have both a hydrophobic component and hydrogen-bonding capabilities. No detectable carryover between runs was noted for the sputtered fibers. The repeatability (RSD%) for a fiber (n = 3) was less than 10% for all analytes tested

  3. Solid rocket motor fire tests: Phases 1 and 2

    Chang, Yale; Hunter, Lawrence W.; Han, David K.; Thomas, Michael E.; Cain, Russell P.; Lennon, Andrew M.


    JHU/APL conducted a series of open-air burns of small blocks (3 to 10 kg) of solid rocket motor (SRM) propellant at the Thiokol Elkton MD facility to elucidate the thermal environment under burning propellant. The propellant was TP-H-3340A for the STAR 48 motor, with a weight ratio of 71/18/11 for the ammonium perchlorate, aluminum, and HTPB binder. Combustion inhibitor applied on the blocks allowed burning on the bottom and/or sides only. Burns were conducted on sand and concrete to simulate near-launch pad surfaces, and on graphite to simulate a low-recession surface. Unique test fixturing allowed propellant self-levitation while constraining lateral motion. Optics instrumentation consisted of a longwave infrared imaging pyrometer, a midwave spectroradiometer, and a UV/visible spectroradiometer. In-situ instrumentation consisted of rod calorimeters, Gardon gauges, elevated thermocouples, flush thermocouples, a two-color pyrometer, and Knudsen cells. Witness materials consisted of yttria, ceria, alumina, tungsten, iridium, and platinum/rhodium. Objectives of the tests were to determine propellant burn characteristics such as burn rate and self-levitation, to determine heat fluxes and temperatures, and to carry out materials analyses. A summary of qualitative results: alumina coated almost all surfaces, the concrete spalled, sand moisture content matters, the propellant self-levitated, the test fixtures worked as designed, and bottom-burning propellant does not self-extinguish. A summary of quantitative results: burn rate averaged 1.15 mm/s, thermocouples peaked at 2070 C, pyrometer readings matched MWIR data at about 2400 C, the volume-averaged plume temperatures were 2300-2400 C with peaks of 2400-2600 C, and the heat fluxes peaked at 125 W/cm2. These results are higher than other researchers' measurements of top-burning propellant in chimneys, and will be used, along with Phase 3 test results, to analyze hardware response to these environments, including General

  4. Observation of Solid-Solid Phase Transitions in Ramp-Compressed Aluminum

    Polsin, D. N.; Boehly, T. R.; Delettrez, J. A.; Gregor, M. C.; McCoy, C. A.; Henderson, B.; Fratanduono, D. E.; Smith, R.; Kraus, R.; Eggert, J. H.; Collins, R.; Coppari, F.; Celliers, P. M.


    We present results of experiments using x-ray diffraction to study the crystalline structure of solid aluminum compressed up to 500 GPa. Aluminum is of interest because it is frequently used as a standard material in high-pressure compression experiments. At ambient pressure and temperature, Al is a face-centered cubic close-packed crystal and has been observed to transform to hexagonal close-packed (hcp) when compressed to 200GPa in a diamond anvil cell. It is predicted to transform from hcp to body-centered cubic when compressed to 315GPa. Laser-driven ramp waves will be used to compress Al to various constant-pressure states. The goal is to investigate the Al phase diagram along its isentrope, i.e., at temperatures 1000K and pressures ranging from 200 to 500 GPa. X-ray diffraction will be used to measure the crystalline structure of the compressed Al and observe the transformations that occur at various pressures. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

  5. Direct unwrapped phase estimation in phase shifting interferometry using Levenberg–Marquardt algorithm

    Kulkarni, Rishikesh; Rastogi, Pramod


    An algorithm for the direct unwrapped phase estimation from the linearly phase shifted interferograms is presented. The temporal fringe intensity along each pixel is represented as a function of fringe amplitude, phase step and the searched phase. These parameters are estimated in the nonlinear least squares sense using the Levenberg–Marquardt algorithm. The proposed method allows the masked interferograms to be handled using a pixel selection approach to provide the appropriate initial conditions at a given pixel utilizing the estimated parameters at one of its neighboring pixels, which results in direct unwrapped phase estimation. Simulation results are provided to evaluate the performance of the proposed method as a function of noise power, spatially varying phase step, number of interferograms and phase step detuning error. The experimental results are also provided in the case of a holographic interferometry setup.

  6. Testing a simple method for computing directly the bulk modulus by NPT simulation: The case of polydisperse hard sphere solids

    Li, Da; Xu, Hong


    The bulk modulus of hard sphere solids has been computed directly by constant pressure Monte-Carlo simulations, using the histogram of the volume fluctuations. In considering first the one-component system, we show that the method is accurate in a large range of pressures, including high-pressure regime. The method is then applied to a polydisperse solid with relatively low polydispersity index. For illustrative purpose, we took a three-component mixture with symmetric size-distribution, and we studied the solid phase (fcc crystal) of this system. Our results show that the equation of state is very sensitive to the polydispersity. Furthermore, in the high-pressure region, where no (accurate) analytical fit for the equation of state exists, our simulations are able to predict the bulk modulus of such systems.

  7. Microwave spectroscopic observation of distinct electron solid phases in wide quantum wells.

    Hatke, A T; Liu, Yang; Magill, B A; Moon, B H; Engel, L W; Shayegan, M; Pfeiffer, L N; West, K W; Baldwin, K W


    In high magnetic fields, two-dimensional electron systems can form a number of phases in which interelectron repulsion plays the central role, since the kinetic energy is frozen out by Landau quantization. These phases include the well-known liquids of the fractional quantum Hall effect, as well as solid phases with broken spatial symmetry and crystalline order. Solids can occur at the low Landau-filling termination of the fractional quantum Hall effect series but also within integer quantum Hall effects. Here we present microwave spectroscopy studies of wide quantum wells that clearly reveal two distinct solid phases, hidden within what in d.c. transport would be the zero diagonal conductivity of an integer quantum-Hall-effect state. Explanation of these solids is not possible with the simple picture of a Wigner solid of ordinary (quasi) electrons or holes.

  8. Phase interface effects in the total enthalpy-based lattice Boltzmann model for solid-liquid phase change

    Huang, Rongzong; Wu, Huiying


    In this paper, phase interface effects, including the differences in thermophysical properties between solid and liquid phases and the numerical diffusion across phase interface, are investigated for the recently developed total enthalpy-based lattice Boltzmann model for solid-liquid phase change, which has high computational efficiency by avoiding iteration procedure and linear equation system solving. For the differences in thermophysical properties (thermal conductivity and specific heat) between solid and liquid phases, a novel reference specific heat is introduced to improve the total enthalpy-based lattice Boltzmann model, which makes the thermal conductivity and specific heat decoupled. Therefore, the differences in thermal conductivity and specific heat can be handled by the dimensionless relaxation time and equilibrium distribution function, respectively. As for the numerical diffusion across phase interface, it is revealed for the first time and found to be induced by solid-liquid phase change. To reduce such numerical diffusion, multiple-relaxation-time collision scheme is exploited, and a special value (one fourth) for the so-called "magic" parameter, a combination of two relaxation parameters, is found. Numerical tests show that the differences in thermophysical properties can be correctly handled and the numerical diffusion across phase interface can be dramatically reduced. Finally, theoretical analyses are carried out to offer insights into the roles of the reference specific heat and "magic" parameter in the treatments of phase interface effects.

  9. Solid phase extraction and determination of carbamate pesticides in water samples by reverse-phase HPLC

    Moreno-Tovar, J.; Santos-Delgado, M.J. [Departamento de Quimica Analitica, Facultad de ciencias Quimicas, Universidad Complutense de Madrid (Spain)


    Solid phase extraction. SPE. using C{sub 1}8 bonded silica cartridges for trace amounts determination of carbaryl, propoxur, thiram, propham and methiocarb in water samples was studied and the breakthrough volume of the cartridges was established. The high enrichment factor and large injection volume admissible in the isocratic reverse-phase HPLC system allows pesticides determination with UV detection at 22o nm even at a concentration lower than 0.05 mug/L. Purified tap natural and underground water samples were spiked with carbamate pesticides in the concentration range 0.16-16.0 mug/L. Large volumes of samples (up to 2L) were passed through available C{sub 1}8, cartridges and eluted with acetonitrile. The preconcentrated samples were analyzed by HPLC using a Spherisorb ODS column with a 42.58 acetonitrile-water mobile phase. From replicate samples, recovery for the pesticides ranged from 79.0 to 103.7% except for thiran which is not retained. Tehe relative standard deviation (n=4 at 0.16 to 1.61 mug/L concetration level) range from 1.1 to 6.8%. (Author) 14 refs.

  10. Single-Phase Direct AC-AC Boost Converter

    LUCANU, M.


    Full Text Available The paper presents a single-phase direct AC-AC boost converter. The circuit of the converter is simple and it has good performances, irrespective of the load nature. The adequate functioning and high performance of the circuit (the efficiency and waveform of the absorbed input current were tested both by simulation and experimentally.

  11. Direct Writing of Microstructures for Solid-State Electronics


    the limits for maskless laser fabrication need to be explored in this area. II. Laser Direct Writing of Metals During our current research, significant...understand these results and extend the analysis to other structures. G. Laser Fabrication Technique to Forming Microcleaved Semiconductor Facets

  12. Characterization of interactions between soil solid phase and soil solution in the initial ecosystem development phase

    Zimmermann, Claudia; Schaaf, Wolfgang


    In the initial phase of soil formation interactions between solid and liquid phases and processes like mineral weathering, formation of reactive surfaces and accumulation of organic matter play a decisive role in developing soil properties. As part of the Transregional Collaborative Research Centre (SFB/TRR 38) 'Patterns and processes of initial ecosystem development' in an artificial catchment, these interactions are studied at the catchment 'Chicken Creek' (Gerwin et al. 2009). To link the interactions between soil solid phase and soil solution at the micro-scale with observed processes at the catchment scale, microcosm experiments under controlled laboratory conditions were carried out. Main objectives were to determine the transformation processes of C and N from litter decomposition within the gaseous, liquid and solid phase, the interaction with mineral surfaces and its role for the establishment of biogeochemical cycles. The microcosm experiments were established in a climate chamber at constant 10 ° C. In total 48 soil columns (diameter: 14.4 cm; height: 30 cm) were filled with two different quaternary substrates (sand and loamy sand) representing the textural variation within the catchment at a bulk density of 1.4-1.5 g*cm-3. The columns were automatically irrigated four times a day with 6.6 ml each (corresponding to 600 mm*yr-1). The gaseous phase in the headspace of the microcosms was analysed continuously for CO2 and N2O contents. C and N transformation processes were studied using 13C and 15N labelled litter of two different plant species occurring at the catchment (Lotus corniculatus, Calamagrostis epigejos) that was incorporated into the microcosm surface. All treatments including a control ran with four replicates over a period of 40 weeks. Two additional microcosms act as pure litter controls where substrate was replaced by glass pearls. Litter and substrate were analysed before and after the experiment. Percolate was continuously collected and

  13. The growth and tensile deformation behavior of the silver solid solution phase with zinc

    Wu, Jiaqi, E-mail: [Department of Electrical Engineering and Computer Science, University of California, Irvine, CA 92697-2660 (United States); Materials and Manufacturing Technology, University of California, Irvine, CA 92697-2660 (United States); Lee, Chin C. [Department of Electrical Engineering and Computer Science, University of California, Irvine, CA 92697-2660 (United States); Materials and Manufacturing Technology, University of California, Irvine, CA 92697-2660 (United States)


    The growth of homogeneous silver solid solution phase with zinc are conducted at two different compositions. X-ray diffraction (XRD) and Scanning electron microscope/Energy dispersive X-ray spectroscopy (SEM/EDX) are carried out for phase identification and chemical composition verification. The mechanical properties of silver solid solution phase with zinc are evaluated by tensile test. The engineering and true stress vs. strain curves are presented and analyzed, with those of pure silver in comparison. According to the experimental results, silver solid solution phase with zinc at both compositions show tempered yield strength, high tensile strength and large uniform strain compared to those of pure silver. Fractography further confirmed the superior ductility of silver solid solution phase with zinc at both compositions. Our preliminary but encouraging results may pave the way for the silver based alloys to be applied in industries such as electronic packaging and structure engineering.

  14. On-line coupling of solid-phase extraction with mass spectrometry for the analysis of biological samples III. Determination of prednisolone in serum

    van Hout, M.W.J.; Hofland, C.M; Niederlander, H.A G; Bruins, A.P.; de Zeeuw, R.A.; de Jong, G.J.


    Solid-phase extraction (SPE) was directly coupled to mass spectrometry (MS) to assess the feasibility of the system for the rapid determination of prednisolone in serum. A C-18 stationary phase allowed washing of the cartridge with 25% methanol. Elution was performed by switching the methanol

  15. On-line coupling of solid-phase extraction with mass spectrometry for the analysis of biological samples III. Determination of prednisolone in serum

    van Hout, MWJ; Hofland, CM; Niederlander, HAG; Bruins, AP; de Zeeuw, RA; de Jong, GJ


    Solid-phase extraction (SPE) was directly coupled to mass spectrometry (MS) to assess the feasibility of the system for the rapid determination of prednisolone in serum. A C-18 stationary phase allowed washing of the cartridge with 25% methanol. Elution was performed by switching the methanol percen

  16. Development of a Paper Spray Mass Spectrometry Cartridge with Integrated Solid Phase Extraction for Bioanalysis.

    Zhang, Chengsen; Manicke, Nicholas E


    A novel paper spray cartridge with an integrated solid phase extraction (SPE) column is described. The cartridge performs extraction and pre-concentration, as well as sample ionization by paper spray, from complex samples such as plasma. The cartridge allows for selective enrichment of target molecules from larger sample volumes and removal of the matrix, which significantly improved the signal intensity of target compounds in plasma samples by paper spray ionization. Detection limits, quantitative performance, recovery, ionization suppression, and the effects of sample volume were evaluated for five drugs: carbamazepine, atenolol, sulfamethazine, diazepam, and alprazolam. Compared with direct paper spray analysis of dried plasma spots, paper spray analysis using the integrated solid phase extraction improved the detection limits significantly by a factor of 14-70, depending on the drug. The improvement in detection limits was, in large part, due to the capability of analyzing larger sample volumes. In addition, ionization suppression was found to be lower and recovery was higher for paper spray with integrated SPE, as compared to direct paper spray analysis. By spiking an isotopically labeled internal standard into the plasma sample, a linear calibration curve for the drugs was obtained from the limit of detection (LOD) to 1 μg/mL, indicating that this method can be used for quantitative analysis. The paper spray cartridge with integrated SPE could prove valuable for analytes that ionize poorly, in applications where lower detection limits are required, or on portable mass spectrometers. The improved performance comes at the cost of requiring a more complex paper spray cartridge and requiring larger sample volumes than those used in typical direct paper spray ionization.

  17. Improved resins and novel materials and methods for solid phase extraction and high performance liquid chromatography

    Freeze, Ronald [Iowa State Univ., Ames, IA (United States)


    Solid-phase extraction (SPE) has grown to be one of the most widely used methods for isolation and preconcentration of a vast range of compounds from aqueous solutions. By modifying polymeric SPE resins with chelating functional groups, the selective uptake of metals was accomplished. The resin, along with adsorbed metals, was vaporized in the ICP and detection of the metals was then possible using either mass or emission spectroscopy. Drug analyses in biological fluids have received heightened attention as drug testing is on the increase both in sports and in the work environment. By using a direct-injection technique, biological fluids can be injected directly into the liquid chromatographic system with no pretreatment. A new surfactant, a sulfonated form of Brij-30 (Brij-S) is shown to prevent the uptake of serum proteins on commercial HPLC columns by forming a thin coating on the silica C18 surface. Excellent separations of eight or more drugs with a wide range of retention times were obtained. The separations had sharper peaks and lower retention times than similar separations performed with the surfactant sodium dodecylsulfate (SDS). Quantitative recovery of a number of drugs with limits of detection near 1 ppm with a 5 μl injection volume were obtained. Finally, a method for solid-phase extraction in a syringe is introduced. The system greatly reduced the volume of solvent required to elute adsorbed analytes from the SPE bed while providing a semi-automated setup. SPE in a syringe consists of a very small bed of resin-loaded membrane packed into a GC or HPLC syringe. After extraction, elution was performed with just a few μl of solvent. This small elution volume allowed injection of the eluent directly from the syringe into the chromatographic system, eliminating the handling problems associated with such small volumes.

  18. Solid phase precipitates in (Zr,Th)-OH-(oxalate, malonate) ternary aqueous system

    Kobayashi, T.; Sasaki, T.; Takagi, I.; Moriyama, H. [Kyoto Univ. (Japan). Dept. of Nuclear Engineering


    The solubility-limiting solid phases in the ternary aqueous systems of Zr(IV)/OH/oxalate, Zr(IV)/OH/malonate, Th(IV)/OH/oxalate and Th(IV)/OH/malonate were characterized by elemental analysis, X-ray diffraction, thermogravimetric analysis and differential thermal analysis. The ternary solid phase of M(IV)/OH/carboxylate was observed to form, even under acidic conditions, depending on the pH and the concentration of carboxylate ligand. In the presence of a large excess of carboxylic acid, however; the binary M(IV)-carboxylate solid phase formed. (orig.)

  19. Design and Synthesis of a Dual Linker for Solid Phase Synthesis of Oleanolic Acid Derivatives

    Shaorong Wang


    Full Text Available A hydrophilic amino-terminated poly(ethylene glycol-type dual linker for solid phase synthesis of oleanolic acid derivatives using trityl chloride resin was designed and synthesized for the first time. Model reactions in both liquid and solid phase were performed to show the feasibility of its selective cleavage at two different sites. The biological assay results indicated that the long and flexible alkyl ether functionality in the linker is less likely to be critical for the binding event. Following the successful solid-phase synthesis of model compounds, the potential of this dual linker in reaction monitoring and target identification is deemed worthy of further study.

  20. Solid-fluid and solid-solid equilibrium in hard sphere united atom models of n-alkanes: rotator phase stability.

    Cao, M; Monson, P A


    We present a study of the phase behavior for models of n-alkanes with chain lengths up to C(21) based on hard sphere united atom models of methyl and methylene groups, with fixed bond lengths and C-C-C bond angles. We extend earlier work on such models of shorter alkanes by allowing for gauche conformations in the chains. We focus particularly on the orientational order about the chain axes in the solid phase near the melting point, and our model shows how the loss of this orientational order leads to the formation of rotator phases. We have made extensive calculations of the thermodynamic properties of the models as well as order parameters for tracking the degree of orientational order around the chain axis. Depending on the chain length and whether the carbon number is even or odd, the model exhibits both a rotator phase and a more orientationally ordered solid phase in addition to the fluid phase. Our results indicate that the transition between the two solid phases is first-order with a small density change. The results are qualitatively similar to those seen experimentally and show that rotator phases can appear in models of alkanes without explicit treatment of attractive forces or explicit treatment of the hydrogen atoms in the chains.

  1. Vapour phase approach for iron oxide nanoparticle synthesis from solid precursors

    Singh, Mandeep; Ulbrich, Pavel; Prokopec, Vadym [Institute of Chemical Technology Prague, Technicka 5, 166 28 Prague 6 (Czech Republic); Svoboda, Pavel [Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 120 00 Prague 2 (Czech Republic); Šantavá, Eva [Institute of Physics ASCR, Na Slovance 2, 182 21 Prague 8 (Czech Republic); Štěpánek, František, E-mail: [Institute of Chemical Technology Prague, Technicka 5, 166 28 Prague 6 (Czech Republic)


    A new non-solution mediated approach to the synthesis of iron oxide nanoparticles directly from solid FeCl{sub 2} salt precursors has been developed. The method is rapid, simple and scalable. The structural properties and the phase of the resulting iron oxide particles has been determined by a range of methods including XRD, FT-IR and Mössbauer spectroscopy, and the phase is shown to be maghemite (γ-Fe{sub 2}O{sub 3}). The magnetic properties of the iron oxide particles have been measured using SQUID, confirming superparamagnetic behaviour of the powder and a saturation magnetization of 53.0 emu g{sup −1} at 300 K. Aqueous dispersions at increasing concentrations were prepared and their heating rate under a 400 kHz alternating magnetic field measured. The specific absorption rate (SAR) of the iron oxide was found to be 84.8 W g{sup −1}, which makes the material suitable for the formulation of ferrofluids or ferrogels with RF heating properties. - Graphical Abstract: Superparamagnetic iron oxide nanoparticles obtained by a novel vapour phase approach. Highlights: ► Novel vapour phase (non-solvent) approach for iron oxide nanoparticle synthesis. ► Attractive alternative approach to the present co-precipitation method. ► Better magnetic properties with high coercivity of nanoparticles. ► A high specific absorption rate (SAR) for hyperthermia applications.

  2. Liquid phase sintering, II: Computer study of skeletal settling and solid phase extrication in a microgravity environment

    Nikolić Z.S.


    Full Text Available A two-dimensional numerical method based on the Brownian motion model and on the Densification model for simulation of liquid phase sintering in microgravity environment will be developed. Both models will be based on domain topology (two-dimensional particle representation and control volume methodology and on three submodels for domain translation, solid skeleton formation and domain extrication. This method will be tested in order to conduct a study of diffusion phenomena and microgravitational effects on microstructural evolution influenced by skeletal settling combined with solid-phase extrication during liquid phase sintering of porous W-Ni system.

  3. Temperature Effects on the Wind Direction Measurement of 2D Solid Thermal Wind Sensors

    Bei Chen; Yan-Qing Zhu; Zhenxiang Yi; Ming Qin; Qing-An Huang


    For a two-dimensional solid silicon thermal wind sensor with symmetrical structure, the wind speed and direction information can be derived from the output voltages in two orthogonal directions, i.e., the north-south and east-west. However, the output voltages in these two directions will vary linearly with the ambient temperature. Therefore, in this paper, a temperature model to study the temperature effect on the wind direction measurement has been developed. A theoretical analysis has been...

  4. Instantaneous oscillatory direction and phase for multivariate timeseries

    Allefeld, Carsten


    This text describes a generalization of the analytic signal (Gabor, 1946) approach for the definition of instantaneous amplitude and phase to the case of multivariate signals. It was originally written as an appendix for another paper, where the determination of the locally dominant oscillatory direction (the instantaneous amplitude) described here is used as a preprocessing step for another kind of data analysis. The text is reproduced in a 'standalone' form because the procedure might prove useful in other contexts too, especially for the purpose of phase synchronization analysis (Rosenblum et al., 1996) between two (or more) multivariate sets of time series (Pascual-Marqui, 2007).

  5. Silica supported Fe(3)O(4) magnetic nanoparticles for magnetic solid-phase extraction and magnetic in-tube solid-phase microextraction: application to organophosphorous compounds.

    Moliner-Martinez, Y; Vitta, Yosmery; Prima-Garcia, Helena; González-Fuenzalida, R A; Ribera, Antonio; Campíns-Falcó, P; Coronado, Eugenio


    This work demonstrates the application of silica supported Fe3O4 nanoparticles as sorbent phase for magnetic solid-phase extraction (MSPE) and magnetic on-line in-tube solid-phase microextraction (Magnetic-IT-SPME) combined with capillary liquid chromatography-diode array detection (CapLC-DAD) to determine organophosphorous compounds (OPs) at trace level. In MSPE, magnetism is used as separation tool while in Magnetic-IT-SPME, the application of an external magnetic field gave rise to a significant improvement of the adsorption of OPs on the sorbent phase. Extraction efficiency, analysis time, reproducibility and sensitivity have been compared. This work showed that Magnetic-IT-SPME can be extended to OPs with successful results in terms of simplicity, speed, extraction efficiency and limit of detection. Finally, wastewater samples were analysed to determine OPs at nanograms per litre.

  6. Phase nucleation and evolution mechanisms in heterogeneous solids

    Udupa, Anirudh

    Phase nucleation and evolution is a problem of critical importance in many applications. As the length scales are reduced, it becomes increasingly important to consider interfacial and micro-structural effects that can be safely ignored at larger length scales owing to randomness. The theory of phase nucleation has been addressed usually by the classical nucleation theory, which was originally derived for single component fluid systems, after making an assumption of equilibrium. The criterion has not been rigorously derived for solids, which are far from equilibrium due to dissipation by multiple physical drivers. In this thesis, a thermodynamically sound nucleation criterion is derived for systems with multiple interacting physical phenomena and multiple dissipating mechanisms. This is done, using the tools of continuum mechanics, by determining the change in free energy upon the introduction of a new nucleus into the system. The developed theory is demonstrated to be a generalization of the classical nucleation theory (CNT). The developed theory is then applied to the problem of electromigration driven void nucleation, a serious reliability concern for the microelectronics industry. The void grows and eventually severs the line making the chip nonfunctional. There are two classes of theories at present in the electromigration literature to address the problem of void nucleation, the vacancy supersaturation theory and the entropic dissipation theory, both of which are empirical and based on intuition developed from experimental observations. When the developed theory was applied to the problem of electromigration, it was found to be consistent with the vacancy supersaturation theory, but provided the correct energetic quantity, the chemical potential, which has contribution from both the vacancy concentration as well as the hydrostatic stress. An experiment, consisting of electromigration tests on serpentine lines, was developed to validate the developed

  7. Utilizing ion-pairing hydrophilic interaction chromatography solid phase extraction for efficient glycopeptide enrichment in glycoproteomics

    Mysling, Simon; Palmisano, Giuseppe; Højrup, Peter;


    Glycopeptide enrichment is a prerequisite to enable structural characterization of protein glycosylation in glycoproteomics. Here we present an improved method for glycopeptide enrichment based on zwitter-ionic hydrophilic interaction chromatography solid phase extraction (ZIC-HILIC SPE...

  8. Study on New Sensitive Method of Determination of Phosphorus by Solid Phase Spectrophotometry


    The use of solid phase spectrophotometry for the determination of trace phosphorus in the system of phosphomolybdate-fructose is described. The adsorption of the system on anion-exchange resin is reported.

  9. Recent Application of Solid Phase Based Techniques for Extraction and Preconcentration of Cyanotoxins in Environmental Matrices.

    Mashile, Geaneth Pertunia; Nomngongo, Philiswa N


    Cyanotoxins are toxic and are found in eutrophic, municipal, and residential water supplies. For this reason, their occurrence in drinking water systems has become a global concern. Therefore, monitoring, control, risk assessment, and prevention of these contaminants in the environmental bodies are important subjects associated with public health. Thus, rapid, sensitive, selective, simple, and accurate analytical methods for the identification and determination of cyanotoxins are required. In this paper, the sampling methodologies and applications of solid phase-based sample preparation methods for the determination of cyanotoxins in environmental matrices are reviewed. The sample preparation techniques mainly include solid phase micro-extraction (SPME), solid phase extraction (SPE), and solid phase adsorption toxin tracking technology (SPATT). In addition, advantages and disadvantages and future prospects of these methods have been discussed.

  10. Design and Solid-Phase Synthesis of Multiple Muramyl Dipeptide (MMD)


    As a non-specific modulator of macrophage, multiplied muramyl dipeptide (MMD) is solid-phase synthesized by application of standard Fmoc chemistry strategy. Tam's multiple antigen system (MAS) is used as our four branched-linker on Lysine.

  11. Solid phase microextraction speciation analysis of triclosan in aqueous mediacontaining sorbing nanoparticles

    Zielinska, K.


    Solid phase microextraction (SPME) is applied in the speciation analysis of the hydrophobic compound triclosan in an aqueous medium containing sorbing SiO2 nanoparticles (NPs). It is found that these NPs, as well as their complexes with triclosan, partition between the bulk medium and the solid

  12. Solid phase microextraction speciation analysis of triclosan in aqueous mediacontaining sorbing nanoparticles

    Zielinska, K.


    Solid phase microextraction (SPME) is applied in the speciation analysis of the hydrophobic compound triclosan in an aqueous medium containing sorbing SiO2 nanoparticles (NPs). It is found that these NPs, as well as their complexes with triclosan, partition between the bulk medium and the solid phas

  13. Solid-phase micro-extraction in bioanalysis, exemplified by lidocaine determination

    de Jong, GJ; Koster, EHM


    Solid-phase micro-extraction (SPME) is a never sample preparation technique that can be used for gaseous, liquid or solid samples in conjunction with GC, HPLC or CE (e.g. [1]). The use of SPME for the analysis of drugs in biofluids is also becoming popular (e.g. [2]). The principle is that a fused s

  14. Strong surface effect on direct bulk flexoelectric response in solids

    Yurkov, A. S. [Ioffe Physical-Technical Institute, 26 Politekhnicheskaya, 194021 St. Petersburg (Russian Federation); Tagantsev, A. K. [Ceramics Laboratory, Swiss Federal Institute of Technology (EPFL), CH-1015 Lausanne (Switzerland); Ioffe Physical-Technical Institute, 26 Politekhnicheskaya, 194021 St. Petersburg (Russian Federation)


    In the framework of a continuum theory, it is shown that the direct bulk flexoelectric response of a finite sample essentially depends on the surface polarization energy, even in the thermodynamic limit where the body size tends to infinity. It is found that a modification of the surface energy can lead to a change in the polarization response by a factor of two. The origin of the effect is an electric field produced by surface dipoles induced by the strain gradient. The unexpected sensitivity of the polarization response to the surface energy in the thermodynamic limit is conditioned by the fact that the moments of the surface dipoles may scale as the body size.

  15. Solid phase radioimmunoassay using labelled antibodies: a conceptual framework for designing assays

    Kalmakoff, J.; Parkinson, A.J.; Crawford, A.M.; Williams, B.R.


    A simple theoretical model for the antigen-antibody reaction is presented and used to evaluate the optimum conditions for designing solid phase radioimmunoassay (RIA) using labelled antibodies. Both theoretical and experimental data are presented, using a wide variety of antigens and their corresponding antibodies. The types of RIA described include the direct, the indirect, and sandwich assays for detecting either antigen or antibody. The experimental results confirm in a semiquantitative manner that the greatest sensitivity of the RIA is achieved when the smallest amount of labelled antibody is used, that whenever possible the antigen/antibody ratio should be greater than unity (greater than 1), and that the formation of the antigen-antibody complex is dependent on the mass action effect.

  16. Solid phase microextraction (SPME) sampling under turbulent conditions and for the simultaneous collecting of tracer gases

    Underwood Susanne W.; Jong Edmund C.; Luxbacher Kray D.; Sarver Emily A.; Ripepi Nino S.; McNair Harold M.


    Solid phase microextraction (SPME) is a solvent-free method of sample collection. SPME is an appealing method for sample collection because it is designed for the sampling of trace level analytes with short sampling times in a variety of environments. Additionally, SPME can be used to directly deliver a sample to a gas chromatograph (GC) for analysis by means of thermal desorption. In this paper, the performance of SPME under dynamic conditions was investigated. Additionally, the competence of SPME sampling for the simultaneous analysis of multiple trace analytes was also evaluated. This work is discussed in the context of underground mine ventilation surveys but is applicable to any industry in which ventilation circuits must be evaluated. The results of this paper showed that the performance of the 100 lm PDMS SPME fiber was both precise and rapid under dynamic conditions. This SPME fiber was also able to simultaneously collect sulfur hexafluoride (SF6) and perfluoromethylcyclohexane (PMCH) with adequate sensitivity.

  17. Thermal desorption solid-phase microextraction inlet for differential mobility spectrometry.

    Rainsberg, Matthew R; de Harrington, Peter B


    A splitless thermal desorber unit that interfaces a differential mobility spectrometry (DMS) sensor has been devised. This device was characterized by the detection of benzene, toluene, and xylene (BTX) in water. The detection of BTX in water is important for environmental monitoring, and ion mobility measurements are traditionally difficult for hydrocarbons in water because water competes for charge and quenches the hydrocarbon signals. This paper reports the use of a DMS with a photoionization source that is directly coupled to a solid-phase microextraction (SPME) desorber. The separation and detection capabilities of the DMS were demonstrated using BTX components. Detection limits for benzene, toluene, and m-xylene were 75, 50, and 5 microg mL(-1), respectively.

  18. Separation and Purification of Sulforaphane from Broccoli by Solid Phase Extraction

    Han, Dandan; Row, Kyung Ho


    A simple solid-phase extraction (SPE) method for the determination of sulforaphane in broccoli has been developed. The optimal conditions were found to be use of a silica SPE cartridge, and ethyl acetate and dichloromethane as washing and eluting solvents, respectively, which could eliminate interferences originating from the broccoli matrix. The extracts were sufficiently clean to be directly injected into high-performance liquid chromatography (HPLC) for further chromatographic analysis. Good linearity was obtained from 0.05 to 200 μg/mL (r = 0.998) for sulforaphane with the relative standard deviations less than 3.6%. The mean recoveries of sulforaphane from broccoli were more than 90.8% and the detection limit (S/N = 3:1) was 0.02 μg/mL. The SPE method provides a higher yield of sulforaphane from crude extracts compared to conventional liquid-liquid extraction. PMID:21673926

  19. A simple and safe method for single HLA-antigen-typing by a solid phase assay.

    Häcker-Shahin, B; Giannitsis, D J


    A rapid solid phase assay for detection of single HLA-antigens on platelets was developed. The platelets were attached to the surface of polystyrene microtitre plate wells by means of a sodium carbonate buffer and centrifugation. Uncovered areas were blocked by a gelatin blocking buffer. After incubation with commercially available anti-HLA-sera the bound anti-HLA-specific antibodies directed against HLA-antigens present on the platelets were made visible by anti-IgG-coated indicator red cells and a brief centrifugation. A positive result, meaning the presence of an HLA-antigen, was indicated by a slight red cell adherence over the reaction surface. In the absence of the HLA-antigen no binding occurred and the indicator red cells formed a small red disc-like pellet.

  20. Separation and Purification of Sulforaphane from Broccoli by Solid Phase Extraction

    Kyung Ho Row


    Full Text Available A simple solid-phase extraction (SPE method for the determination of sulforaphane in broccoli has been developed. The optimal conditions were found to be use of a silica SPE cartridge, and ethyl acetate and dichloromethane as washing and eluting solvents, respectively, which could eliminate interferences originating from the broccoli matrix. The extracts were sufficiently clean to be directly injected into high-performance liquid chromatography (HPLC for further chromatographic analysis. Good linearity was obtained from 0.05 to 200 μg/mL (r = 0.998 for sulforaphane with the relative standard deviations less than 3.6%. The mean recoveries of sulforaphane from broccoli were more than 90.8% and the detection limit (S/N = 3:1 was 0.02 μg/mL. The SPE method provides a higher yield of sulforaphane from crude extracts compared to conventional liquid-liquid extraction.

  1. Isostructural solid-solid phase transition in monolayers of soft core-shell particles at fluid interfaces: structure and mechanics.

    Rey, Marcel; Fernández-Rodríguez, Miguel Ángel; Steinacher, Mathias; Scheidegger, Laura; Geisel, Karen; Richtering, Walter; Squires, Todd M; Isa, Lucio


    We have studied the complete two-dimensional phase diagram of a core-shell microgel-laden fluid interface by synchronizing its compression with the deposition of the interfacial monolayer. Applying a new protocol, different positions on the substrate correspond to different values of the monolayer surface pressure and specific area. Analyzing the microstructure of the deposited monolayers, we discovered an isostructural solid-solid phase transition between two crystalline phases with the same hexagonal symmetry, but with two different lattice constants. The two phases corresponded to shell-shell and core-core inter-particle contacts, respectively; with increasing surface pressure the former mechanically failed enabling the particle cores to come into contact. In the phase-transition region, clusters of particles in core-core contacts nucleate, melting the surrounding shell-shell crystal, until the whole monolayer moves into the second phase. We furthermore measured the interfacial rheology of the monolayers as a function of the surface pressure using an interfacial microdisk rheometer. The interfaces always showed a strong elastic response, with a dip in the shear elastic modulus in correspondence with the melting of the shell-shell phase, followed by a steep increase upon the formation of a percolating network of the core-core contacts. These results demonstrate that the core-shell nature of the particles leads to a rich mechanical and structural behavior that can be externally tuned by compressing the interface, indicating new routes for applications, e.g. in surface patterning or emulsion stabilization.

  2. Detailed Multi-dimensional Modeling of Direct Internal Reforming Solid Oxide Fuel Cells.

    Tseronis, K; Fragkopoulos, I S; Bonis, I; Theodoropoulos, C


    Fuel flexibility is a significant advantage of solid oxide fuel cells (SOFCs) and can be attributed to their high operating temperature. Here we consider a direct internal reforming solid oxide fuel cell setup in which a separate fuel reformer is not required. We construct a multidimensional, detailed model of a planar solid oxide fuel cell, where mass transport in the fuel channel is modeled using the Stefan-Maxwell model, whereas the mass transport within the porous electrodes is simulated using the Dusty-Gas model. The resulting highly nonlinear model is built into COMSOL Multiphysics, a commercial computational fluid dynamics software, and is validated against experimental data from the literature. A number of parametric studies is performed to obtain insights on the direct internal reforming solid oxide fuel cell system behavior and efficiency, to aid the design procedure. It is shown that internal reforming results in temperature drop close to the inlet and that the direct internal reforming solid oxide fuel cell performance can be enhanced by increasing the operating temperature. It is also observed that decreases in the inlet temperature result in smoother temperature profiles and in the formation of reduced thermal gradients. Furthermore, the direct internal reforming solid oxide fuel cell performance was found to be affected by the thickness of the electrochemically-active anode catalyst layer, although not always substantially, due to the counter-balancing behavior of the activation and ohmic overpotentials.

  3. Solid Phase Equilibria in the Pi-Ga-As and Pt-Ga-Sb Systems


    OFFICE OF NAVAL RESEARCH Research Contract N00014-87-K-0014 R&T Code 413E026---01 AD-A 198 654 TECHNICAL REPORT No. 9 SOLID PHASE EQUILIBRIA IN THE...Classtcation) UNCLASSLFIED: Tech.Rept.#9 SOLID PHASE EQUILIBRIA IN T11: Pt-Ga-As AND Pt-Ga-Sb SYST’IS 12 PERSONAL AuTiOR(S) C.T. Tsai and R.S. Williats 13a TYPE

  4. Molecularly imprinted polymers: New molecular recognition materials for selective solid-phase extraction of organic compounds

    Martín Esteban, A.


    During the last few years molecularly imprinted polymers have appeared as new selective sorbents for solid-phase extraction of organic compounds in different samples. Molecular imprinting technology involves the preparation of a polymer with specific recognition sites for certain molecules. Once the polymer has been obtained, it can be used in solid-phase extraction protocols, where a careful selection of the most appropriate solvents to be used in the different steps (sample loading, washing...

  5. Expedient protocol for solid-phase synthesis of secondary and tertiary amines

    Olsen, Christian A; Witt, Matthias; Jaroszewski, Jerzy W


    [reaction: see text] An expedient solid-phase synthetic approach to secondary and tertiary amines was developed. The protocol employs conversion of resin-bound amino alcohols to the corresponding iodides, followed by iodide displacement with primary or secondary amines or with unprotected amino...... alcohols. This two-step procedure, affording products in good to excellent yields, is suitable for solid-phase synthesis of polyamines....

  6. Isotope effects in dense solid hydrogen - Phase transition in deuterium at 190 + or - 20 GPa

    Hemley, R. J.; Mao, H. K.


    Raman measurements of solid normal deuterium compressed in a diamond-anvil cell indicate that the material undergoes a structural phase transformation at 190 + or - 20 GPa and 77 K. Spectroscopically, the transition appears analogous to that observed in hydrogen at 145 + or - 5 GPa. The large isotope effect on the transition pressure suggests there is a significant vibrational contribution to the relative stability of the solid phases of hydrogen at very high densities.

  7. Multivariate Quantification of the Solid State Phase Composition of Co-Amorphous Naproxen-Indomethacin

    Beyer, Andreas; Grohganz, Holger; Löbmann, Korbinian


    regression approach that enables the simultaneous determination of up to four solid state fractions: crystalline naproxen, γ-indomethacin, α-indomethacin as well as co-amorphous naproxen-indomethacin. For this purpose, a calibration set that covers the whole range of possible combinations of the four...... four solid state phases, involving one co-amorphous phase, can be quantified with this XRPD data-based approach....

  8. Solid-Phase Synthesis of PEGylated Lipopeptides Using Click Chemistry

    Jølck, Rasmus Irming; Berg, Rolf Henrik; Andresen, Thomas Lars


    A versatile methodology for efficient synthesis of PEGylated lipopeptides via CuAAC “Click” conjugation between alkyne-bearing solid-supported lipopeptides and azido-functionalized PEGs is described. This new and very robust method offers a unique platform for synthesizing PEGylated lipopeptides...

  9. Molecularly imprinted solid-phase extraction for the screening of antihyperglycemic biguanides.

    Feng, Sherry Y; Lai, Edward P C; Dabek-Zlotorzynska, Ewa; Sadeghi, Susan


    A new molecularly imprinted polymer (MIP) was specifically synthesized as a smart material for the recognition of metformin hydrochloride in solid-phase extraction. Particles of this MIP were packed into a stainless-steel tubing (50 mm x 0.8 mm i.d.) equipped with an exit frit. This micro-column was employed in the development of a molecularly imprinted solid-phase extraction (MISPE) method for metformin determination. The MISPE instrumentation consisted of a micrometer pump, an injector valve equipped with a 20-microl sample loop, a UV detector, and an integrator. With CH3CN as the mobile phase flowing at 0.5 ml/min, 95 +/- 2% binding could be achieved for 1200 ng of metformin from one injection of a phosphate-buffered sample solution (pH 2.5). Methanol + 3% trifluoroacetic acid was good for quantitative pulsed elution (PE) of the bound metformin. The MISPE-PE method, with UV detection at 240 nm, afforded a detection limit of 16 ng (or 0.8 microg/ml) for metformin. However, the micro-column interacted indiscriminately with phenformin with a 49 +/- 2% binding. A systematic investigation of binding selectivity was conducted with respect to sample composition (including the solvent, matrix, pH, buffer and surfactant effects). An intermediate step of differential pulsed elution used acetonitrile with 5% picric acid to remove phenformin and other structural analogues. A final pulsed elution of metformin for direct UV detection was achieved using 3% trifluoroacetic acid in methanol.

  10. Direct Phase Equilibrium Simulations of NIPAM Oligomers in Water.

    Boţan, Vitalie; Ustach, Vincent; Faller, Roland; Leonhard, Kai


    NIPAM (N-isopropylacrylamide)-based polymers in water show many interesting properties in experiments, including a lower critical solution temperature (LCST) at 305 K and a conformational transition of single chains at the same temperature. The results of many simulation studies suggest that standard force fields are able to describe the conformational transition and the phase equilibrium well. We show by performing long molecular dynamics simulations of the direct liquid-liquid phase equilibrium of NIPAM trimers in water that there is no LCST in the expected temperature range for any of the force fields under study. The results show further that the relaxation times of single-chain simulations are considerably longer than anticipated. Conformational transitions of single polymers can therefore not necessarily be used as surrogates for a real phase transition.

  11. Direct atomic structure determination by the inspection of structural phase.

    Nakashima, Philip N H; Moodie, Alexander F; Etheridge, Joanne


    A century has passed since Bragg solved the first atomic structure using diffraction. As with this first structure, all atomic structures to date have been deduced from the measurement of many diffracted intensities using iterative and statistical methods. We show that centrosymmetric atomic structures can be determined without the need to measure or even record a diffracted intensity. Instead, atomic structures can be determined directly and quickly from the observation of crystallographic phases in electron diffraction patterns. Furthermore, only a few phases are required to achieve high resolution. This represents a paradigm shift in structure determination methods, which we demonstrate with the moderately complex α-Al2O3. We show that the observation of just nine phases enables the location of all atoms with a resolution of better than 0.1 Å. This level of certainty previously required the measurement of thousands of diffracted intensities.

  12. Effects of direct ultrasonic treatment on microstructure and elongation of semi-solid Sn-62Bi alloy

    Hui-ting Zheng


    Full Text Available A new direct ultrasonic treatment (DUT setup with the ultrasonic horn placed in the horizontal direction was developed and used in the preparation of semi-solid Sn-62Bi slurry. The influence of DUT temperature on microstructure and properties of Sn-62Bi alloy were studied. The test results of XRD showed that the semi-solid Sn-62Bi alloy obtained by the DUT process exhibits pronounced preferential orientation of Bi (2 0 2, Bi (-1 1 1, Bi (-2 0 1, Sn (1 1 0 and Sn (2 2 0 planes. Compared to the conventional liquid casting Sn-62Bi alloy without DUT, it was discovered that the primary Bi blocks of semi-solid Sn-62Bi alloy prepared with the DUT process distribute more homogeneously and are smaller. With the treatment by ultrasonic vibration in the semi-solid state for 120 s, the higher the primary Bi phase fraction in the slurry, the smaller the size of primary semi-solid Bi blocks formed after solidification. The average side length of the primary Bi blocks was from 30 μm to 80 μm. The elongation of Sn-62Bi alloy treated by DUT for 120 s at 145 °C is 43.21%, reflecting a distinctly improvement by 129.10%, as compared to the conventional liquid casting Sn-62Bi alloy without DUT. This indicates that DUT process could improve dramatically the ductility of Sn-62Bi alloys content. The microstructure evolution mechanism of semi-solid Sn-62Bi alloy slurry was also analyzed.

  13. Plasma mitomycin C concentrations determined by HPLC coupled to solid-phase extraction.

    Paroni, R; Arcelloni, C; De Vecchi, E; Fermo, I; Mauri, D; Colombo, R


    The aim of this study was to set up a method for quantification of plasma mitomycin C (MMC) concentrations during intravesical chemotherapy delivered in the presence of local bladder hyperthermia (HT). In comparison with existing methods, this assay, characterized by relative simplicity and efficiency, resulted in the facilitation of performance with nondedicated instrumentation or nonspecialized staff. Purification from plasma matrix was carried out by solid-phase extraction under vaccuum. The purified drug was then collected directly into the vials of the HPLC autosampler. Chromatographic analysis was performed on a reversed-phase C18 column with water:acetonitrile (85:15 by vol) as the mobile phase and the UV detector set at 365 nm. The use of porfiromycin as internal standard provided a method with good within-day precision (CV 6.0% at 5 micrograms/L, n = 6), linearity (0.5-50 micrograms/L), and specificity. The lower limit of detection (< or = 0.5 microgram/L) proved to be suitable for plasma pharmacokinetics monitoring in two tested patients treated with MMC + HT for superficial bladder cancer.

  14. Numerical Simulation of Erosion-Corrosion in the Liquid Solid Two-Phase Flow


    Erosion-corrosion of liquid-solid two-phase flow occurring in a pipe with sudden expansion in cross section is numerically simulated in this paper. The global model for erosion-corrosion process includes three main components: the liquid-solid two-phase flow model, erosion model and corrosion model. The Euierian-Lagranglan approach is used to simulate liquid-solid two-phase flow, while the stochastic trajectory model was adopted to obtain properties of particle phase. Two-way coupling effect between the fluid and the particle phase is considered in the model. The accuracy of the models is tested by the data in the reference. The comparison shows that the model is basically correct and feasible.

  15. Enabling Technologies for Direct Detection Optical Phase Modulation Formats

    Xu, Xian

    Phase modulation formats are believed to be one of the key enabling techniques for next generation high speed long haul fiber-optic communication systems due to the following main advantages: (1) with a balanced detection, a better receiver sensitivity over conventional intensity modulation formats, e.g., a ˜3-dB sensitivity improvement using differential phase shift keying (DPSK) and a ˜1.3-dB sensitivity improvement using differential quadrature phase shift keying (DQPSK); (2) excellent robustness against fiber nonlinearities; (3) high spectrum efficiency when using multilevel phase modulation formats, such as DQPSK. As the information is encoded in the phase of the optical field, the phase modulation formats are sensitive to the phase-related impairments and the deterioration induced in the phase-intensity conversion. This consequently creates new challenging issues. The research objective of this thesis is to depict some of the challenging issues and provide possible solutions. The first challenge is the cross-phase modulation (XPM) penalty for the phase modulated channels co-propagating with the intensity modulated channels. The penalty comes from the pattern dependent intensity fluctuations of the neighboring intensity modulated channels being converted into phase noise in the phase modulation channels. We propose a model to theoretically analyze the XPM penalty dependence on the walk off effect. From this model, we suggest that using fibers with large local dispersion or intentionally introducing some residual dispersion per span would help mitigate the XPM penalty. The second challenge is the polarization dependent frequency shift (PDf) induced penalty during the phase-intensity conversion. The direct detection DPSK is usually demodulated in a Mach-Zehnder delay interferometer (DI). The polarization dependence of DI introduces a PDf causing a frequency offset between the laser's frequency and the transmissivity peak of DI, degrading the demodulated DPSK

  16. Phase transitions of amorphous solid acetone in confined geometry investigated by reflection absorption infrared spectroscopy.

    Shin, Sunghwan; Kang, Hani; Kim, Jun Soo; Kang, Heon


    We investigated the phase transformations of amorphous solid acetone under confined geometry by preparing acetone films trapped in amorphous solid water (ASW) or CCl4. Reflection absorption infrared spectroscopy (RAIRS) and temperature-programmed desorption (TPD) were used to monitor the phase changes of the acetone sample with increasing temperature. An acetone film trapped in ASW shows an abrupt change in the RAIRS features of the acetone vibrational bands during heating from 80 to 100 K, which indicates the transformation of amorphous solid acetone to a molecularly aligned crystalline phase. Further heating of the sample to 140 K produces an isotropic solid phase, and eventually a fluid phase near 157 K, at which the acetone sample is probably trapped in a pressurized, superheated condition inside the ASW matrix. Inside a CCl4 matrix, amorphous solid acetone crystallizes into a different, isotropic structure at ca. 90 K. We propose that the molecularly aligned crystalline phase formed in ASW is created by heterogeneous nucleation at the acetone-water interface, with resultant crystal growth, whereas the isotropic crystalline phase in CCl4 is formed by homogeneous crystal growth starting from the bulk region of the acetone sample.

  17. Peritectic phase growth in directionally solidified Cu-70% Sn alloy

    L(U) HaiYan; LI ShuangMing; LIU Lin; FU HengZhi


    The growth mechanism of the peritectic η phase involving the peritectic reaction and peritectic transformation in Cu-70%Sn alloy was investigated under directional solidification. The results show that a major growth mechanism in thickening of the peritectic η-layer is not the peritectic reaction but the peritectic transformation. The transformation temperature and isothermal time play crucial roles in determining the volume fraction and the thickness of the peritectic η phase. With the increase of the temperature and isothermal time, the volume fraction of the peritectic η phase increases. The regressed data show that the relationship between the thickness of η phase (△x) and the transformation temperature (T) meets the following equation ln △x=6.5-16731/T. Additionally, there exists a relationship between the thickness of the η phase (△x) and the isothermal time (t) at the 9 mm solidification distance below the peritectic reaction interface, △x =0.72t1/2, which is consistent with the theoretical model.

  18. Evaporation induced orientational order in soft solid phases of clays

    Lindbo Hansen, Elisabeth; Hemmen, Henrik; Dommersnes, Paul; Fossum, Jon Otto


    We demonstrate experimentally the possibility for promoting uniaxial orientational order in initially isotropic, soft solid dispersions of the synthetic clays Na-fluorohectorite and Laponite RD. We observe that strong orientational order can emerge from initially isotropic states when the samples are subjected to a slow concentration increase through evaporation of the dispersion water. During evaporation, there is a gradient in the order which, if evaporation is halted, slowly relaxes towards a uniform order throughout the samples. It is evident that the development of orientational order is not counterindicated by the viscoelastic nature of the samples, and that although the translational and likely also rotational diffusion of the particles is restricted in the soft solid state, the orientational degree of freedom can undergo a transition from a collectively random to an ordered state.

  19. New insights in Microbial Fuel Cells: novel solid phase anolyte

    Tommasi, Tonia; Salvador, Gian Paolo; Quaglio, Marzia


    For the development of long lasting portable microbial fuel cells (MFCs) new strategies are necessary to overcome critical issues such as hydraulic pump system and the biochemical substrate retrieval overtime to sustain bacteria metabolism. The present work proposes the use of a synthetic solid anolyte (SSA), constituted by agar, carbonaceous and nitrogen sources dissolved into diluted seawater. Results of a month-test showed the potential of the new SSA-MFC as a long lasting low energy consuming system.

  20. Solid-liquid phase diagram of disubstituted benzene systems

    黑恩成; 刘国杰


    The cooling curves of different compositions of the systems of ortho-chlorotoluene/para-chlorotoluene and ortho-nitrochlorobenzene/para-nitrochlorobenzene are carefully determined by the thermal analysis method. The crystals obtained are also tested. The conclusion that both systems are of simple eutectic diagram but not the solid solution diagram with a minimum melting point is confirmed. The characteristics of the diagram are explained according to the physical and thermodynarmc properties of the components.

  1. Phase transition of solid bismuth under high pressure

    Chen, Hai-Yan; Xiang, Shi-Kai; Yan, Xiao-Zhen; Zheng, Li-Rong; Zhang, Yi; Liu, Sheng-Gang; Bi, Yan


    As a widely used pressure calibrator, the structural phase transitions of bismuth from phase I, to phase II, to phase III, and then to phase V with increasing pressure at 300 K have been widely confirmed. However, there are different structural versions for phase III, most of which are determined by x-ray diffraction (XRD) technology. Using x-ray absorption fine structure (XAFS) measurements combined with ab initio calculations, we show that the proposed incommensurate composite structure of bismuth of the three configurations is the best option. An abnormal continuous increase of the nearest-neighbor distance of phase III with elevated pressure is also observed. The electronic structure transformation from semimetal to metal is responsible for the complex behavior of structure transformation. Project supported by the National Natural Science Foundation of China (Grant Nos. 10904133, 11304294, 11274281, 11404006, and U1230201), the Development Foundation of China Academy of Engineering Physics (Grant Nos. 2015B0101004, 2013B0401062, and 2012A0101001), the Research Foundation of the Laboratory of Shock Wave and Detonation, China (Grant No. 9140C670201140C67282).

  2. Effect of shear stress in ferroelectric solid solutions with coexisting phases

    Lu, Xiaoyan; Zhang, Hangbo; Zheng, Limei; Cao, Wenwu


    One common feature of ferroelectric solid solutions with large piezoelectricity is the coexistence of two or more phases. Due to the strain mismatch among coexisting phases, adaptive structures near the interfaces or domain walls develop to maintain the atomic coherency. Shear stresses commonly exist, especially when the domain size is small. The effect of shear stresses on phase morphology in Pb(Zr1-xTix)O3 solid solutions with compositions within the morphotropic phase boundary region was studied within the framework of Landau phenomenological theory. Our results show that the coexisting rhombohedral (R) and tetragonal (T) phases can be modified to form stable or metastable R-like and/or T-like monoclinic phases under shear stresses. Large stresses may also induce first order or second order phase transitions.

  3. Temperature and phase dependence of positron lifetimes in solid cyclohexane

    Eldrup, Morten Mostgaard


    The temperature dependence of position lifetimes in both the brittle and plastic phases of cyclohaxane has been examined. Long-lived components in both phases are associated with the formation of positronium (Ps). Two long lifetimes attributable to ortho-Ps are resolvable in the plastic phase....... The longer of these (≈ 2.5 ns), which is temperature dependent, is ascribed to ortho-Ps trapped at vacancies. The shorter lifetime (≈ 0.9 ns), shows little temperature dependence. In contrast to most other plastic crystals, no sigmoidal behaviour of the average ortho-Ps lifetime is observed. A possibility...

  4. Solid-liquid phase equilibria of the Gaussian core model fluid.

    Mausbach, Peter; Ahmed, Alauddin; Sadus, Richard J


    The solid-liquid phase equilibria of the Gaussian core model are determined using the GWTS [J. Ge, G.-W. Wu, B. D. Todd, and R. J. Sadus, J. Chem. Phys. 119, 11017 (2003)] algorithm, which combines equilibrium and nonequilibrium molecular dynamics simulations. This is the first reported use of the GWTS algorithm for a fluid system displaying a reentrant melting scenario. Using the GWTS algorithm, the phase envelope of the Gaussian core model can be calculated more precisely than previously possible. The results for the low-density and the high-density (reentrant melting) sides of the solid state are in good agreement with those obtained by Monte Carlo simulations in conjunction with calculations of the solid free energies. The common point on the Gaussian core envelope, where equal-density solid and liquid phases are in coexistence, could be determined with high precision.

  5. Dynamics of Vibrio cholerae abundance in Austrian saline lakes, assessed with quantitative solid-phase cytometry.

    Schauer, Sonja; Jakwerth, Stefan; Bliem, Rupert; Baudart, Julia; Lebaron, Philippe; Huhulescu, Steliana; Kundi, Michael; Herzig, Alois; Farnleitner, Andreas H; Sommer, Regina; Kirschner, Alexander


    In order to elucidate the main predictors of Vibrio cholerae dynamics and to estimate the risk of Vibrio cholera-related diseases, a recently developed direct detection approach based on fluorescence in situ hybridization and solid-phase cytometry (CARD-FISH/SPC) was applied in comparison to cultivation for water samples from the lake Neusiedler See, Austria and three shallow alkaline lakes over a period of 20 months. Vibrio cholerae attached to crustacean zooplankton was quantified via FISH and epifluorescence microscopy. Concentrations obtained by CARD-FISH/SPC were significantly higher than those obtained by culture in 2011, but were mostly of similar magnitude in 2012. Maximum cell numbers were 1.26 × 10(6) V. cholerae per L in Neusiedler See and 7.59 × 10(7) V. cholerae per L in the shallow alkaline lakes. Only on a few occasions during summer was the crustacean zooplankton the preferred habitat for V. cholerae. In winter, V. cholerae was not culturable but could be quantified at all sites with CARD-FISH/SPC. Beside temperature, suspended solids, zooplankton and ammonium were the main predictors of V. cholerae abundance in Neusiedler See, while in the shallow alkaline lakes it was organic carbon, conductivity and phosphorus. Based on the obtained concentrations a first estimation of the health risk for visitors of the lake could be performed. © 2015 The Authors. Environmental Microbiology published by Society for Applied Microbiology and John Wiley & Sons Ltd.

  6. Solid-phase cloning for high-throughput assembly of single and multiple DNA parts.

    Lundqvist, Magnus; Edfors, Fredrik; Sivertsson, Åsa; Hallström, Björn M; Hudson, Elton P; Tegel, Hanna; Holmberg, Anders; Uhlén, Mathias; Rockberg, Johan


    We describe solid-phase cloning (SPC) for high-throughput assembly of expression plasmids. Our method allows PCR products to be put directly into a liquid handler for capture and purification using paramagnetic streptavidin beads and conversion into constructs by subsequent cloning reactions. We present a robust automated protocol for restriction enzyme based SPC and its performance for the cloning of >60 000 unique human gene fragments into expression vectors. In addition, we report on SPC-based single-strand assembly for applications where exact control of the sequence between fragments is needed or where multiple inserts are to be assembled. In this approach, the solid support allows for head-to-tail assembly of DNA fragments based on hybridization and polymerase fill-in. The usefulness of head-to-tail SPC was demonstrated by assembly of >150 constructs with up to four DNA parts at an average success rate above 80%. We report on several applications for SPC and we suggest it to be particularly suitable for high-throughput efforts using laboratory workstations.

  7. Evaluation of a molecularly imprinted polymer for determination of steroids in goat milk by matrix solid phase dispersion.

    Gañán, Judith; Morante-Zarcero, Sonia; Gallego-Picó, Alejandrina; Garcinuño, Rosa María; Fernández-Hernando, Pilar; Sierra, Isabel


    A molecularly imprinted polymer-matrix solid-phase dispersion methodology for simultaneous determination of five steroids in goat milk samples was proposed. Factors affecting the extraction recovery such as sample/dispersant ratio and washing and elution solvents were investigated. The molecularly imprinted polymer used as dispersant in the matrix solid-phase dispersion procedure showed high affinity to steroids, and the obtained extracts were sufficiently cleaned to be directly analyzed. Analytical separation was performed by micellar electrokinetic chromatography using a capillary electrophoresis system equipped with a diode array detector. A background electrolyte composed of borate buffer (25mM, pH 9.3), sodium dodecyl sulfate (10mM) and acetonitrile (20%) was used. The developed MIP-MSPD methodology was applied for direct determination of testosterone (T), estrone (E1), 17β-estradiol (17β-E2), 17α-ethinylestradiol (EE2) and progesterone (P) in different goat milk samples. Mean recoveries obtained ranged from 81% to 110%, with relative standard deviations (RSD)≤12%. The molecularly imprinted polymer-matrix solid-phase dispersion method is fast, selective, cost-effective and environment-friendly compared with other pretreatment methods used for extraction of steroids in milk.

  8. Preparation and characterization of porous carbon material-coated solid-phase microextraction metal fibers.

    Zhu, Fang; Guo, Jiaming; Zeng, Feng; Fu, Ruowen; Wu, Dingcai; Luan, Tiangang; Tong, Yexiang; Lu, Tongbu; Ouyang, Gangfeng


    Two kinds of porous carbon materials, including carbon aerogels (CAs), wormhole-like mesoporous carbons (WMCs), were synthesized and used as the coatings of solid-phase microextraction (SPME) fibers. By using stainless steel wire as the supporting core, six types of fibers were prepared with sol-gel method, direct coating method and direct coating plus sol-gel method. Headspace SPME experiments indicated that the extraction efficiencies of the CA fibers are better than those of the WMC fibers, although the surface area of WMCs is much higher than that of CAs. The sol-gel-CA fiber (CA-A) exhibited excellent extraction properties for non-polar compounds (BTEX, benzene, toluene, ethylbenzene, o-xylene), while direct-coated CA fiber (CA-B) presented the best performance in extracting polar compounds (phenols). The two CA fibers showed wide linear ranges, low detection limits (0.008-0.047μgL(-1) for BTEX, 0.15-5.7μgL(-1) for phenols) and good repeatabilities (RSDs less than 4.6% for BTEX, and less than 9.5% for phenols) and satisfying reproducibilities between fibers (RSDs less than 5.2% for BTEX, and less than 9.9% for phenols). These fibers were successfully used for the analysis of water samples from the Pearl River, which demonstrated the applicability of the home-made CA fibers.

  9. Study of solid solution strengthening of alloying element with phase structure factors


    Using the empirical electron theory of solids and molecules (EET), the phase structure factors, nA and nB, of the carbon-containing structural units with mass fraction of carbon (wC) below 0.8% and the mono-alloy structural units with wC at 0.2% in austenite and martensite are calculated. The solid solution strengthening brought by C-containing interstitial solid solution and alloy-substitutional solid solution in γ-Fe and α-Fe is discussed at electron structural level. The coefficient (s) of solid solution strengthening is advanced according to the bonding force between atoms. The study shows that when the criterion is applied to the carbonaceous or alloying element-containing solid solution the results of calculation will coincide with the experimental result very well.

  10. Determination of Roxarsone in feeds using solid phase extraction and liquid chromatography with ultraviolet detection.

    Sapp, R E; Davidson, S


    A method is presented for detection and quantitation of Roxarsone in poultry feed by liquid chromatography. The drug is extracted by phosphate buffer and determined by solid phase extraction and reversed-phase liquid chromatography. Recoveries of the sample spikes and fortified field samples agree closely with those obtained by the standard spectrophotometric method.


    TANG Xuelin; QIAN Zhongdong; WU Yulin


    The dense solid-phase governing equations for two-phase flows are obtained by using the kinetic theory of gas molecules. Assuming that the solid-phase velocity distributions obey the Maxwell equations, the collision term for particles under dense two-phase flow conditions is also derived.In comparison with the governing equations of a dilute two-phase flow, the solid-particle's governing equations are developed for a dense turbulent solid-liquid flow by adopting some relevant terms from the dilute two-phase governing equations. Based on Cauchy-Helmholtz theorem and Smagorinsky model,a second-order dynamic sub-grid-scale (SGS) model, in which the sub-grid-scale stress is a function of both the strain-rate tensor and the rotation-rate tensor, is proposed to model the two-phase governing equations by applying dimension analyses. Applying the SIMPLEC algorithm and staggering grid system to the two-phase discretized governing equations and employing the slip boundary conditions on the walls, the velocity and pressure fields, and the volumetric concentration are calculated. The simulation results are in a fairly good agreement with experimental data in two operating cases in a conduit with a rectangular cross-section and these comparisons imply that these models are practical.

  12. Nonequilibrium stationary states and phase transitions in directed Ising models

    Godrèche, Claude; Bray, Alan J.


    We study the nonequilibrium properties of directed Ising models with non-conserved dynamics, in which each spin is influenced by only a subset of its nearest neighbours. We treat the following models: (i) the one-dimensional chain; (ii) the two-dimensional square lattice; (iii) the two-dimensional triangular lattice and (iv) the three-dimensional cubic lattice. We raise and answer the question: (a) under what conditions is the stationary state described by the equilibrium Boltzmann-Gibbs distribution? We show that, for models (i), (ii) and (iii), in which each spin 'sees' only half of its neighbours, there is a unique set of transition rates, namely with exponential dependence in the local field, for which this is the case. For model (iv), we find that any rates satisfying the constraints required for the stationary measure to be Gibbsian should satisfy detailed balance, ruling out the possibility of directed dynamics. We finally show that directed models on lattices of coordination number z>=8 with exponential rates cannot accommodate a Gibbsian stationary state. We conjecture that this property extends to any form of the rates. We are thus led to the conclusion that directed models with Gibbsian stationary states only exist in dimensions one and two. We then raise the question: (b) do directed Ising models, augmented by Glauber dynamics, exhibit a phase transition to a ferromagnetic state? For the models considered above, the answers are open problems, with the exception of the simple cases (i) and (ii). For Cayley trees, where each spin sees only the spins further from the root, we show that there is a phase transition provided the branching ratio, q, satisfies q>=3.

  13. Traveling waves for models of phase transitions of solids driven by configurational forces

    Kawashima, Shuichi


    This article is concerned with the existence of traveling wave solutions, including standing waves, to some models based on configurational forces, describing respectively the diffusionless phase transformations of solid materials, e.g., Steel, and phase transitions due to interface motion by interface diffusion, e.g., Sintering. These models are recently proposed by Alber and Zhu. We consider both the order-parameter-conserved case and the non-conserved one, under suitable assumptions. Also we compare our results with the corresponding ones for the Allen-Cahn and the Cahn-Hilliard equations coupled with linear elasticity, which are models for diffusion-dominated phase transformations in elastic solids.

  14. Density-functional theory of a lattice-gas model with vapour, liquid, and solid phases

    Prestipino, S.; Giaquinta, P. V.


    We use the classical version of the density-functional theory in the weighted-density approximation to build up the entire phase diagram and the interface structure of a two-dimensional lattice-gas model which is known, from previous studies, to possess three stable phases -- solid, liquid, and vapour. Following the common practice, the attractive part of the potential is treated in a mean-field-like fashion, although with different prescriptions for the solid and the fluid phases. It turns o...

  15. Direct phasing from Patterson syntheses by δ recycling.

    Rius, Jordi


    The direct methods origin-free modulus sum function [Rius (1993). Acta Cryst. A49, 406-409] includes in its definition the structure factor G(Φ) of the squared crystal structure expressed in terms of Φ, the set of φ phases of the normalized structure factors E's of the crystal structure of unit-cell volume V. Here the simpler sum function variant S'(P) = ∑(H)E(-H)∫(V)δ(P,Δ)(Φ)exp(i2πHr)dV extended over all H reflections is introduced which involves no G's and in which the δ(P,Δ) function corresponds to δ(P) = FT(-1){(E(2)(H) - )exp[iφ(H)(Φ)]} (where FT = Fourier transform) with all values smaller than Δ = 2.5σ(P) equated to zero (σ(2)(P) is the variance of δ(P) calculable from the experimental intensities). The new phase estimates are obtained by Fourier transforming δ(P,Δ). This iterative phasing method (δ recycling) only requires calculation of Fourier transforms at two stages. Since δ(M) ≃ δ(P)/2, similar arguments are valid for δ(M) = FT(-1)[(E(H) - )exp(iφ(H))] from which the corresponding S'(M) phasing function follows.

  16. Solid-phase microextraction for bioconcentration studies according to OECD TG 305

    Duering, Rolf-Alexander; Boehm, Leonard [Land Use and Nutrition (IFZ) Justus Liebig University Giessen, Institute of Soil Science and Soil Conservation, Research Centre for BioSystems, Giessen (Germany); Schlechtriem, Christian [Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Schmallenberg (Germany)


    An important aim of the European Community Regulation on chemicals and their safe use is the identification of (very) persistent, (very) bioaccumulative, and toxic substances. In other regulatory chemical safety assessments (pharmaceuticals, biocides, pesticides), the identification of such (very) persistent, (very) bioaccumulative, and toxic substances is of increasing importance. Solid-phase microextraction is especially capable of extracting total water concentrations as well as the freely dissolved fraction of analytes in the water phase, which is available for bioconcentration in fish. However, although already well established in environmental analyses to determine and quantify analytes mainly in aqueous matrices, solid-phase microextraction is still a rather unusual method in regulatory ecotoxicological research. Here, the potential benefits and drawbacks of solid-phase microextraction are discussed as an analytical routine approach for aquatic bioconcentration studies according to OECD TG 305, with a special focus on the testing of hydrophobic organic compounds characterized by log K{sub OW}> 5. (orig.)

  17. Detecting Lesch-Nyhan syndrome by solid phase primer extension

    Shumaker, J.M.; Caskey, C.T. [Baylor College of Medicine, Houston, TX (United States); Metspalu, A.


    A mutation detection method based upon the wild type human HPRT sequence is presented for identification of Lesch Nyhan syndrome. The technique consists of performing a biotinlyated PCR amplification of the region of interest, followed by isolation and purification of single stranded template using magnetic separation. Allele-specific primers are annealed adjacent to the potential mutation site on the template. A terminal fluorescent deoxynucleotide addition is performed with a DNA template-dependent polymerase to distinguish between the mutant and wild-type sequence. The products are purified from unincorporated ddNTPs, eluted and finally analyzed on an ABI 373 to identify the mutation. The length of an extension primer is used as a position signature for mutations. The fidelity of nucleotide incorporation provides an excellent signal-to-noise ratio for the detection of nine HPRT mutations within eight cell lines. This method should detect all types of mutations except for repeated sequences that are longer than the primers. Moreover, the method is being extended to a solid support assay, whereby the extension primers are attached to a two-dimensional glass surface. Following extension, the solid support is analyzed for radioactive incorporation. We have shown the sequence determination of a five base region of a wild-type sequence and two different HPRT mutations. As more dense oligonucleotide arrays are produced, this method could be extended to sequence the complete coding region of HPRT.

  18. Pentaerythrityltetramine scaffolds for solid-phase combinatorial chemistry.

    Virta, Pasi; Leppänen, Marika; Lönnberg, Harri


    Straightforward synthesis for two pentaerythrityltetramine precursors, 2,2-bis(azidomethyl)propane-1,3-diamine (1) and 2-[N-(allyloxycarbonyl)aminomethyl]-2-azidomethylpropane-1,3-diamine (2), has been described. Both propane-1,3-diamines have been attached by reductive amination to a solid-supported backbone amide linker derived from 4-(4-formyl-3,5-dimethoxyphenoxy)butyric acid. The presence of the two methoxy substituents on the linker is essential to avoid cross-linking between two linkers. The remaining free primary amino group of the propane-1,3-diamine moiety may then be selectively acylated with an appropriately protected amino acid using conventional N,N-dicyclohexylcarbodiimide/1-hydroxybenzotriazole (DCC/HOBt) activation without any interference by the secondary amino function. The latter group may be subsequently acylated by an anhydride method. Sequential reduction of the azido group and removal of the allyloxycarbonyl protection from 2 allow further coupling of two different amino acids, and hence, this handle may be utilized in construction of branched structures containing four different amino acids or peptides. Solid-supported 1 may, in turn, be used for the synthesis of similar constructs containing two identical branches. It is worth noting that no acid-labile protecting groups are required in this approach, and hence, this dimension may be saved for the cleavage of the linker. The applicability of the scaffolds to library synthesis has been demonstrated by preparation of 11 pentaerythrityl-branched tetra- and octapeptides.

  19. Stability of phases in (Ba, Gd)MnO3 solid solution system

    Migaku Kobayashi; Hidenori Tamura; Hiromi Nakano; Hirohisa Satoh; Naoki Kamegashira


    The existing phases in BaxGd1-xMnO3 solid solution system (0≦x≦1) were studied by analyzing the detailed crystal structure of each composition from the results of the Rietveld method using powder X-ray diffraction data. For a small substitution of Ba for Gd (0≦x<0.1), the orthorhombic phase with a perovskite type structure (Pnma space group) was stably formed and this fact was supported by the electron diffraction data. There existed an intermediate phase of Ba0.33Gd0.67MnO3, which was characterized as the tetragonal phase with perovskite structure. The composition range of this phase was narrow and almost line compound. Between the regions of these phases, there existed two-phase region. There was also a two-phase region between the intermediate tetragonal phase and BaMnO3. Measurement of electrical conductivities of these orthorhombic solid solutions and tetragonal phases showed semiconducting behaviors for both phases and the existence of the phase transition at high temperature for the orthorhombic phase. The transition temperature decreased as the Ba content increased.

  20. Crystalline-to-plastic phase transitions in molecularly thin n-dotriacontane films adsorbed on solid surfaces

    Cisternas, Edgardo; Corrales, T. P.; del Campo, V.;


    Crystalline-to-rotator phase transitions have been widely studied in bulk hydrocarbons, in particular in normal alkanes. But few studies of these transitions deal with molecularly thin films of pure n-alkanes on solid substrates. In this work, we were able to grow dotriacontane (n-C32H66) films...... identify with a solid-solid phase transition. At higher coverages, we observed additional steps in the ellipsometric signal that we identify with a solid-solid phase transition in multilayer islands (similar to 333 K) and with the transition to the rotator phase in bulk crystallites (similar to 337 K...

  1. Rapidly Activated Dynamic Phase Transitions in Nonlinear Solids


    I Form Approv# edAD -A263 601 AiENTA11ON PAGE- f____________18 1. AGENCY USE ONLY (Lea"e blaWk 12. REPORT DATE 13. REPORT TYPE AND OATES COVEREO Feb...phase transforming media during high energy impact. Conversion of mechanical energy to thermal ener- gy has been studied by means of an extended theory...and Phase Structures in General Media , R. Fosdick, E. Dunn & M. Slemrod eds., IMA volume series, Springer- Verlag. Song, J. and T. L. Pence (1992

  2. Two-phase anaerobic digestion of vegetable market waste fraction of municipal solid waste and development of improved technology for phase separation in two-phase reactor.

    Majhi, Bijoy Kumar; Jash, Tushar


    Biogas production from vegetable market waste (VMW) fraction of municipal solid waste (MSW) by two-phase anaerobic digestion system should be preferred over the single-stage reactors. This is because VMW undergoes rapid acidification leading to accumulation of volatile fatty acids and consequent low pH resulting in frequent failure of digesters. The weakest part in the two-phase anaerobic reactors was the techniques applied for solid-liquid phase separation of digestate in the first reactor where solubilization, hydrolysis and acidogenesis of solid organic waste occur. In this study, a two-phase reactor which consisted of a solid-phase reactor and a methane reactor was designed, built and operated with VMW fraction of Indian MSW. A robust type filter, which is unique in its implementation method, was developed and incorporated in the solid-phase reactor to separate the process liquid produced in the first reactor. Experiments were carried out to assess the long term performance of the two-phase reactor with respect to biogas production, volatile solids reduction, pH and number of occurrence of clogging in the filtering system or choking in the process liquid transfer line. The system performed well and was operated successfully without the occurrence of clogging or any other disruptions throughout. Biogas production of 0.86-0.889m(3)kg(-1)VS, at OLR of 1.11-1.585kgm(-3)d(-1), were obtained from vegetable market waste, which were higher than the results reported for similar substrates digested in two-phase reactors. The VS reduction was 82-86%. The two-phase anaerobic digestion system was demonstrated to be stable and suitable for the treatment of VMW fraction of MSW for energy generation.

  3. A rapid solid-phase extraction fluorometric method for thiamine and riboflavin in salmonid eggs

    Zajicek, James L.; Tillitt, Donald E.; Brown, Scott B.; Brown, Lisa R.; Honeyfield, Dale C.; Fitzsimons, John D.


    A new method has been developed and successfully applied to the selective measurement of thiamine (nonphosphorylated), total thiamine (sum of thiamine, thiamine monophosphate [TMP], thiamine diphosphate [TDP], and thiamine triphosphate [TTP]), and potentially interfering riboflavin in acidic (2% trichloroacetic acid) extracts of selected salmonid and walleye egg samples. Acidic extracts of eggs were applied directly to end-capped C18, reversed-phase solid-phase extraction (SPE) columns and separated into three fractions by elution with mixtures of PO4 buffer (pH 2), methanol (10%), and acetonitrile (20%). All thiamine compounds recovered in the first two fractions were oxidized to their corresponding thiochromes with alkaline potassium hexacyanoferrate, and we measured the thiochrome fluorescence (excitation at 360 nm, emission at 460 nm) in a 96-well microplate reader. Riboflavin, recovered in third fraction (eluted with pH 2, 20% acetonitrile), was analyzed directly by measuring the fluorescence of this fraction (excitation at 450 nm, emission at 530 nm). Significant portions of the phosphate esters of thiamine (TMP, TDP, and presumably TTP), when present at low concentrations (thiamine per gram of egg), were not retained by the 100-mg SPE column, and were collected directly during sample loading and in a subsequent phosphoric acid rinse as fraction 1. Free thiamine (nonphosphorylated) and remaining portions of the TDP and TMP were then eluted in the second fraction with 10% methanol/PO4 buffer, whereas the un-ionized, relatively nonpolar riboflavin was eluted in the third fraction with 20% acetonitrile. This new method uses a traditional sample homogenization of egg tissue to extract thiamine compounds into 2% trichlororacetic acid solution; an inexpensive, commercially available SPE column; small amounts of sample (0.5-1 g); microliter volumes of solvents per sample; a traditional, relatively nonhazardous, oxidation of thiamine compounds to fluorescent

  4. A review on solid phase extraction of actinides and lanthanides with amide based extractants.

    Ansari, Seraj A; Mohapatra, Prasanta K


    Solid phase extraction is gaining attention from separation scientists due to its high chromatographic utility. Though both grafted and impregnated forms of solid phase extraction resins are popular, the later is easy to make by impregnating a given organic extractant on to an inert solid support. Solid phase extraction on an impregnated support, also known as extraction chromatography, combines the advantages of liquid-liquid extraction and the ion exchange chromatography methods. On the flip side, the impregnated extraction chromatographic resins are less stable against leaching out of the organic extractant from the pores of the support material. Grafted resins, on the other hand, have a higher stability, which allows their prolong use. The goal of this article is a brief literature review on reported actinide and lanthanide separation methods based on solid phase extractants of both the types, i.e., (i) ligand impregnation on the solid support or (ii) ligand functionalized polymers (chemically bonded resins). Though the literature survey reveals an enormous volume of studies on the extraction chromatographic separation of actinides and lanthanides using several extractants, the focus of the present article is limited to the work carried out with amide based ligands, viz. monoamides, diamides and diglycolamides. The emphasis will be on reported applied experimental results rather than on data pertaining fundamental metal complexation. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. GMTI Direction of Arrival Measurements from Multiple Phase Centers.

    Doerry, Armin W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bickel, Douglas L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)


    Ground Moving Target Indicator (GMTI) radar attempts to detect and locate targets with unknown motion. Very slow-moving targets are difficult to locate in the presence of surrounding clutter. This necessitates multiple antenna phase centers (or equivalent) to offer independent Direction of Arrival (DOA) measurements. DOA accuracy and precision generally remains dependent on target Signal-to-Noise Ratio (SNR), Clutter-toNoise Ratio (CNR), scene topography, interfering signals, and a number of antenna parameters. This is true even for adaptive techniques like Space-Time-AdaptiveProcessing (STAP) algorithms.

  6. Positronium in solid phases of n-alkane binary mixtures

    Zgardzińska, B.; Goworek, T.


    Highlights: • Rotator phase in even alkanes C{sub n}H{sub 2n+2} with n ⩽ 20 appears in mixed samples only. • Interlamellar gap width is the same for shorter chain alkane concentration x and 1 − x. • Excess electron trapping diminishes with broadening of alkane chain distribution Δn. - Abstract: Binary mixtures of even-numbered normal alkanes C{sub n}H{sub 2n+2} and C{sub n+2}H{sub 2n+6} with n ⩽ 18 were investigated by positron annihilation spectroscopy. Formation of the rotator phase was observed in mixed structures, while no such a phase in neat alkanes in this range of n was found. Phase diagrams for n = 18 and n = 16 are very similar to the diagrams for binary mixtures of odd-numbered alkanes. The effect of positronium formation with trapped excess electrons weakens with decreasing n, at low n values the time constant of Ps rise contains the component much shorter than 1 h.

  7. All rights reserved Development of Headspace Solid-Phase ...


    Pesticide Residues in Fruit and Vegetable Samples using OFAT Design. *. 1,2. LUKMAN BOLA ... phase microextraction parameters (fiber coating type, extraction temperature and time, pH, salt addition ... production of food (Bakırcı, et al. 2014 ...

  8. SANS study of phase separation in solid {sup 3}He-{sup 4}He

    Koster, J.P.; Nagler, S.E.; Adams, E.D. [Florida Univ., Gainesville, FL (United States). Dept. of Physics; Wignall, G.D. [Oak Ridge National Lab., TN (United States). Solid State Div.


    Small angle neutron scattering has been used to study phase separation in a quantum alloy, solid {sup 3}He{sub x}-{sup 4}He{sub 1{minus}x}. The onset of phase separation is marked by a dramatic increase in the measured scattering. A simple interpretation of the results suggests that the late-stage phase separation kinetics are dominated by an increase in the concentration of {sup 3}He atoms in preexisting precipitate regions.

  9. Phase transitions for scaling of structural correlations in directed networks

    van der Hoorn, Pim


    Analysis of degree-degree dependencies in complex networks, and their impact on processes on networks requires null models, i.e. models that generate uncorrelated scale-free networks. Most models to date however show structural negative dependencies, caused by finite size effects. We analyze the behavior of these structural negative degree-degree dependencies, using rank based correlation measures, in the directed Erased Configuration Model. We obtain expressions for the scaling as a function of the exponents of the distributions. Moreover, we show that this scaling undergoes a phase transition, where one region exhibits scaling related to the natural cut-off of the network while another region has scaling similar to the structural cut-off for uncorrelated networks. By establishing the speed of convergence of these structural dependencies we are able to asses statistical significance of degree-degree dependencies on finite complex networks when compared to networks generated by the directed Erased Configurati...

  10. The detection of transient directional couplings based on phase synchronization

    Wagner, T; Fell, J; Lehnertz, K, E-mail: twagner@uni-bonn.d [Department of Epileptology, University of Bonn, Sigmund-Freud-Strasse 25, 53127 Bonn (Germany)


    We extend recent approaches based on the concept of phase synchronization to enable the time-resolved investigation of directional relationships between coupled dynamical systems from short and transient noisy time series. For our approach, we consider an observed ensemble of a sufficiently large number of time series as multiple realizations of a process. We derive an index that quantifies the direction of transient interactions and assess its statistical significance using surrogate techniques. Analysing time series from noisy and chaotic systems, we demonstrate numerically the applicability and limitations of our approach. Our findings from an exemplary application to event-related brain activities underline the importance of our method for improving knowledge about the mechanisms underlying memory formation in humans.

  11. Direct determination of three-phase contact line properties on nearly molecular scale

    Winkler, P. M.; McGraw, R. L.; Bauer, P. S.; Rentenberger, C.; Wagner, P. E.


    Wetting phenomena in multi-phase systems govern the shape of the contact line which separates the different phases. For liquids in contact with solid surfaces wetting is typically described in terms of contact angle. While in macroscopic systems the contact angle can be determined experimentally, on the molecular scale contact angles are hardly accessible. Here we report the first direct experimental determination of contact angles as well as contact line curvature on a scale of the order of 1nm. For water nucleating heterogeneously on Ag nanoparticles we find contact angles around 15 degrees compared to 90 degrees for the corresponding macroscopically measured equilibrium angle. The obtained microscopic contact angles can be attributed to negative line tension in the order of ‑10‑10 J/m that becomes increasingly dominant with increasing curvature of the contact line. These results enable a consistent theoretical description of heterogeneous nucleation and provide firm insight to the wetting of nanosized objects.

  12. Thermoelastic properties of solid phases: C++ object oriented library “SolidEOS”

    Churakov, Sergey V.


    A new object-oriented C++ library (SolidEOS) for calculating the thermoelastic properties of solids is presented. The implementation is based on the Mie-Grüneisen-Debye equation of state (EOS) augmented by lowest order correction for anharmonicity. Several commonly used static EOS like Birch-Murnaghan and Vinet models are available. Although some widely used approximation for the Debye-Grüneisen parameter and static EOS are implemented, the final behaviour of the EOS can be easily modified by overloading predefined virtual functions. The article provides a basic physical background of the modern theory of high-pressure EOS. The detailed documentation of the class hierarchy is summarized in the appendix, which accompanies the source. Several examples of practical use are given in the appendix as well. The library is appropriate for applications in geophysics, petrology, material science or any other field where thermodynamic and elastic properties of solids are relevant. The source code is available from the Computers & Geoscience software archive.

  13. Theoretical study on phase coexistence in ferroelectric solid solutions near the tricritical point

    Lu, Xiaoyan, E-mail:, E-mail:; Li, Hui [Key Lab of Structures Dynamic Behavior and Control of the Ministry of Education, School of Civil Engineering, Harbin Institute of Technology, Harbin 150001 (China); Zheng, Limei [Condensed Matter Science and Technology Institute, Harbin Institute of Technology, Harbin 150001 (China); Cao, Wenwu [Condensed Matter Science and Technology Institute, Harbin Institute of Technology, Harbin 150001 (China); Department of Mathematics and Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States)


    Phase coexistence in ferroelectric solid solutions near the tricritical point has been theoretically analyzed by using the Landau-Devonshire theory. Results revealed that different phases having similar potential wells could coexist in a narrow composition range near the tricritical point in the classical Pb(Zr{sub 1−x}Ti{sub x})O{sub 3} system. The potential barrier between potential wells increases with the decrease of temperature. Coexisting phases or different domains of the same phase can produce adaptive strains to maintain atomic coherency at the interfaces or domain walls. Such compatibility strains have influence on the energy potential as well as the stability of relative phases, leading to the appearance of energetically unfavorable monoclinic phases. Those competing and coexisting phases also construct an easy phase transition path with small energy barrier in between, so that very small stimuli can produce large response in compositions near the morphotropic phase boundary, especially near the tricritical point.

  14. Transitional phenomenon of particle dispersion in gas-solid two-phase flows

    LUO Kun; FAN JianRen; CEN KeFa


    Without using any turbulent model, direct numerical simulation of a three-dimensional gas-solid two-phase turbulent jet was performed by finite volume method. The effects on dispersion of particles with different Stokes numbers by the transitional behavior of turbulent structures were investigated. To produce high-resolution results and reduce the computation and storage, the fractional-step projection algorithm was used to solve the governing equations of gas phase fluid. The low-storage, three-order Runge-Kutta scheme was used for time integration. The governing equations of particles were solved in the Lagrangian framework. These numerical schemes were validated by the good agreement between the statistical results of flow field and the related experimental data. In the study of particle dispersion, it was found that the effects on particle dispersion by the spanwise vortex structures were prominent. The new behaviors of particle dispersion were also observed during the evolution of the flow field, i.e. the transitional phenomenon of particle dispersion occurs for the particles with small and intermediate Stokes numbers.

  15. Optimizing the solid-phase immunofiltration assay. A rapid alternative to immunoassays.

    IJsselmuiden, O E; Herbrink, P; Meddens, M J; Tank, B; Stolz, E; Van Eijk, R V


    The technical variables of the solid-phase immunofiltration assay (SPIA) for the detection of antibodies bound to antigens on a solid-phase filter have been investigated. The binding to solid-phase filters of 125I-labelled axial filament proteins derived from Treponema phagedenis and the optimal conditions for blocking non-specific protein binding were analysed. Axial filament was applied to nitrocellulose, Hybond Nylon and Zeta Probe. After extensive rinsing, the highest amount (68%) of axial filament was observed bound to Zeta Probe. However, blocking non-specific protein binding by pre-wetting the filter with rinsing buffer containing 0.5% Tween 20, prevented the binding of protein to the filter only when nitrocellulose was used as solid phase. Tween 20 (0.5%) in the rinsing and incubation solutions was found to be necessary for the reduction of non-specific binding of contaminants in turbid sera. However, the use of such solutions resulted in a substantial leakage of antigen (47%) during rinsing procedures. Binding of antigen-specific antibody was analysed using 125I-labelled protein A. The maximal possible binding of the antibody occurred within 5 min when the antibody solution was filtered. For optimal binding of 125I-labelled protein A an incubation time of 1 h was needed. It is suggested that solid-phase immunofiltration may provide a rapid alternative for radioimmunoassays or enzyme immunoassays for the detection of specific antibodies.

  16. Determination of melamine in aquaculture feed samples based on molecularly imprinted solid-phase extraction.

    Lian, Ziru; Liang, Zhenlin; Wang, Jiangtao


    This research highlights the application of highly efficient molecularly imprinted solid-phase extraction for the preconcentration and analysis of melamine in aquaculture feed samples. Melamine-imprinted polymers were synthesized employing methacrylic acid and ethylene glycol dimethacrylate as functional monomer and cross-linker, respectively. The characteristics of obtained polymers were evaluated by scanning electron microscopy, Fourier transform infrared spectroscopy and binding experiments. The imprinted polymers showed an excellent adsorption ability for melamine and were applied as special solid-phase extraction sorbents for the selective cleanup of melamine. An off-line molecularly imprinted solid-phase extraction procedure was developed for the separation and enrichment of melamine from aquaculture feed samples prior to high-performance liquid chromatography analysis. Optimum molecularly imprinted solid-phase extraction conditions led to recoveries of the target in spiked feed samples in the range 84.6-96.6% and the relative standard deviation less than 3.38% (n = 3). The aquaculture feed sample was determined, and there was no melamine found. The results showed that the molecularly imprinted solid-phase extraction protocols permitted the sensitive, uncomplicated and inexpensive separation and pre-treatment of melamine in aquaculture feed samples.

  17. A High-Throughput Process for the Solid-Phase Purification of Synthetic DNA Sequences.

    Grajkowski, Andrzej; Cieślak, Jacek; Beaucage, Serge L


    An efficient process for the purification of synthetic phosphorothioate and native DNA sequences is presented. The process is based on the use of an aminopropylated silica gel support functionalized with aminooxyalkyl functions to enable capture of DNA sequences through an oximation reaction with the keto function of a linker conjugated to the 5'-terminus of DNA sequences. Deoxyribonucleoside phosphoramidites carrying this linker, as a 5'-hydroxyl protecting group, have been synthesized for incorporation into DNA sequences during the last coupling step of a standard solid-phase synthesis protocol executed on a controlled pore glass (CPG) support. Solid-phase capture of the nucleobase- and phosphate-deprotected DNA sequences released from the CPG support is demonstrated to proceed near quantitatively. Shorter than full-length DNA sequences are first washed away from the capture support; the solid-phase purified DNA sequences are then released from this support upon reaction with tetra-n-butylammonium fluoride in dry dimethylsulfoxide (DMSO) and precipitated in tetrahydrofuran (THF). The purity of solid-phase-purified DNA sequences exceeds 98%. The simulated high-throughput and scalability features of the solid-phase purification process are demonstrated without sacrificing purity of the DNA sequences. © 2017 by John Wiley & Sons, Inc. Copyright © 2017 John Wiley & Sons, Inc.

  18. Thermodynamic analysis of Direct Urea Solid Oxide Fuel Cell in combined heat and power applications

    Abraham, F.; Dincer, I.


    This paper presents a comprehensive steady state modelling and thermodynamic analysis of Direct Urea Solid Oxide Fuel Cell integrated with Gas Turbine power cycle (DU-SOFC/GT). The use of urea as direct fuel mitigates public health and safety risks associated with the use of hydrogen and ammonia. The integration scheme in this study covers both oxygen ion-conducting solid oxide fuel cells (SOFC-O) and hydrogen proton-conducting solid oxide fuel cells (SOFC-H). Parametric case studies are carried out to investigate the effects of design and operating parameters on the overall performance of the system. The results reveal that the fuel cell exhibited the highest level of exergy destruction among other system components. Furthermore, the SOFC-O based system offers better overall performance than that with the SOFC-H option mainly due to the detrimental reverse water-gas shift reaction at the SOFC anode as well as the unique configuration of the system.

  19. The synthesis and properties of the phases obtained by solid-solid reactions

    Blonska-Tabero A.


    Full Text Available The presented work encompasses the subject of the studies and the results obtained over the last years by the research workers of the Department of Inorganic Chemistry. They include mainly the studies on the reactivity of metal oxides, searching for new phases in binary and ternary systems of metal oxides as well as describing phase relations establishing in such systems. They also encompass works on the extensive characteristics of physico-chemical properties of the newly obtained compounds.

  20. Characterization of MEMS a Directional Microphone with Solid and Perforated Wings


    Animals use two basic acoustics cues, interaural time and amplitude differences, for the directional binaural detection of a sound source. From the...goal of this research is to characterize two micro electro mechanical system (MEMS) based directional sound sensors with solid and perforated and responses to incident sound at different angles were measured using a laser vibrometer. Both sensors showed good sound coupling and measured

  1. Direct transformation of carbohydrates to the biofuel 5-ethoxymethylfurfural by solid acid catalysts

    Li, Hu; Shunmugavel, Saravanamurugan; Yang, Song;


    The direct conversion of glucose to 5-ethoxymethylfurfural (EMF) is a promising biomass transformation due to the products potential application as a biofuel. Here, the conversion of glucose to EMF was examined over several solid acid catalysts in ethanol between 96 and 125 oC. Among the catalyst...

  2. Cholesterol transport via ABCA1: new insights from solid-phase binding assay.

    Reboul, Emmanuelle; Dyka, Frank M; Quazi, Faraz; Molday, Robert S


    It is now well established that the ATP-binding cassette transporter A1 (ABCA1) plays a pivotal role in HDL metabolism, reverse cholesterol transport and net efflux of cellular cholesterol and phospholipids. We aimed to resolve some uncertainties related to the putative function of ABCA1 as a mediator of lipid transport by using a methodology developed in the laboratory to isolate a protein and study its interactions with other compounds. ABCA1 was tagged with the 1D4 peptide at the C terminus and expressed in human HEK 293 cells. Preliminary experiments showed that the tag modified neither the protein expression/localization within the cells nor the ability of ABCA1 to promote cholesterol cellular efflux to apolipoprotein A-I. ABCA1-1D4 was then purified and reconstituted in liposomes. ABCA1 displayed an ATPase activity in phospholipid liposomes that was significantly decreased by cholesterol. Finally, interactions with either cholesterol or apolipoprotein A-I were assessed by binding experiments with protein immobilized on an immunoaffinity matrix. Solid-phase binding assays showed no direct binding of cholesterol or apolipoprotein A-I to ABCA1. Overall, our data support the hypothesis that ABCA1 is able to mediate the transport of cholesterol from cells without direct interaction and that apo A-I primarily binds to membrane surface or accessory protein(s).

  3. Solid-phase extraction procedures in systematic toxicological analysis

    Franke, J.P.; de Zeeuw, R.A


    In systematic toxicological analysis (STA) the substance(s) present is (are) not known at the start of the analysis. in such an undirected search the extraction procedure cannot be directed to a given substance but must be a general procedure where a compromise must be reached in that the substances

  4. Studies on solid phase synthesis,characterization and fluorescent property of the new rare earth complexes

    Shi, Jianwei; Xiaoxu TENG; Wang, Linling; Long, Rong


    Rare earth-β-diketone ligand complex luminescent material has stable chemical properties and excellent luminous property. Using europium oxide and (γ-NTA) as raw materials, novel rare earth-β-dione complexes are synthesized by solid state coordination chemistry. The synthesis temperature and milling time are discussed for optimization. Experimental results show that the suitable reaction situation is at 50 ℃ and 20 h for solid-phase synthesis. The compositions and structures of the complexes...

  5. Solid solution, phase separation, and cathodoluminescence of GaP-ZnS nanostructures.

    Liu, Baodan; Bando, Yoshio; Dierre, Benjamin; Sekiguchi, Takashi; Golberg, Dmitri; Jiang, Xin


    Quaternary solid-solution nanowires made of GaP and ZnS have been synthesized through well-designed synthetic routines. The as-synthesized GaP-ZnS solid-solution nanowires exhibit decent crystallinity with the GaP phase as the host, while a large amount of twin structural defects are observed in ZnS-rich nanowires. Cathodoluminescence studies showed that GaP-rich solid-solution nanowires have a strong visible emission centered at 600 nm and the ZnS-rich solid-solution nanowires exhibited a weak emission peak in the UV range and a broad band in the range 400-600 nm. The formation mechanism, processes, and optical emissions of GaP-ZnS solid-solution nanowires were discussed in detail.

  6. The solid-liquid phase diagrams of binary mixtures of consecutive, even saturated fatty acids.

    Costa, Mariana C; Sardo, Mariana; Rolemberg, Marlus P; Coutinho, João A P; Meirelles, Antonio J A; Ribeiro-Claro, Paulo; Krähenbühl, M A


    For the first time, the solid-liquid phase diagrams of five binary mixtures of saturated fatty acids are here presented. These mixtures are formed of caprylic acid (C(8:0))+capric acid (C(10:0)), capric acid (C(10:0))+lauric acid (C(12:0)), lauric acid (C(12:0))+myristic acid (C(14:0)), myristic acid (C(14:0))+palmitic acid (C(16:0)) and palmitic acid (C(16:0))+stearic acid (C(18:0)). The information used in these phase diagrams was obtained by differential scanning calorimetry (DSC), X-ray diffraction (XRD), FT-Raman spectrometry and polarized light microscopy, aiming at a complete understanding of the phase diagrams of the fatty acid mixtures. All of the phase diagrams reported here presented the same global behavior and it was shown that this was far more complex than previously imagined. They presented not only peritectic and eutectic reactions, but also metatectic reactions, due to solid-solid phase transitions common in fatty acids and regions of solid solution not previously reported. This work contributes to the elucidation of the phase behavior of these important biochemical molecules, with implications in various industrial applications.

  7. Characterization of rhamnolipids by liquid chromatography/mass spectrometry after solid-phase extraction.

    Behrens, Beate; Engelen, Jeannine; Tiso, Till; Blank, Lars Mathias; Hayen, Heiko


    Rhamnolipids are surface-active agents with a broad application potential that are produced in complex mixtures by bacteria of the genus Pseudomonas. Analysis from fermentation broth is often characterized by laborious sample preparation and requires hyphenated analytical techniques like liquid chromatography coupled to mass spectrometry (LC-MS) to obtain detailed information about sample composition. In this study, an analytical procedure based on chromatographic method development and characterization of rhamnolipid sample material by LC-MS as well as a comparison of two sample preparation methods, i.e., liquid-liquid extraction and solid-phase extraction, is presented. Efficient separation was achieved under reversed-phase conditions using a mixed propylphenyl and octadecylsilyl-modified silica gel stationary phase. LC-MS/MS analysis of a supernatant from Pseudomonas putida strain KT2440 pVLT33_rhlABC grown on glucose as sole carbon source and purified by solid-phase extraction revealed a total of 20 congeners of di-rhamnolipids, mono-rhamnolipids, and their biosynthetic precursors 3-(3-hydroxyalkanoyloxy)alkanoic acids (HAAs) with different carbon chain lengths from C8 to C14, including three rhamnolipids with uncommon C9 and C11 fatty acid residues. LC-MS and the orcinol assay were used to evaluate the developed solid-phase extraction method in comparison with the established liquid-liquid extraction. Solid-phase extraction exhibited higher yields and reproducibility as well as lower experimental effort.

  8. Mixed Model for Silt-Laden Solid-Liquid Two-Phase Flows

    唐学林; 徐宇; 吴玉林


    The kinetic theory of molecular gases was used to derive the governing equations for dense solid-liquid two-phase flows from a microscopic flow characteristics viewpoint by multiplying the Boltzmann equation for each phase by property parameters and integrating over the velocity space. The particle collision term was derived from microscopic terms by comparison with dilute two-phase flow but with consideration of the collisions between particles for dense two-phase flow conditions and by assuming that the particle-phase velocity distribution obeys the Maxwell equations. Appropriate terms from the dilute two-phase governing equations were combined with the dense particle collision term to develop the governing equations for dense solid-liquid turbulent flows. The SIMPLEC algorithm and a staggered grid system were used to solve the discretized two-phase governing equations with a Reynolds averaged turbulence model. Dense solid-liquid turbulent two-phase flows were simulated for flow in a duct. The simulation results agree well with experimental data.

  9. Solid-Phase Synthesis of Amine/Carboxyl Substituted Prolines and Proline Homologues: Scope and Limitations.

    Zhou, Ziniu; Scott, William L; O'Donnell, Martin J


    A solid-phase procedure is used to synthesize racemic peptidomimetics based on the fundamental peptide unit. The peptidomimetics are constructed around proline or proline homologues variably substituted at the amine and carbonyl sites. The procedure expands the diversity of substituted peptidomimetic molecules available to the Distributed Drug Discovery (D3) project. Using a BAL-based solid-phase synthetic sequence the proline or proline homologue subunit is both constructed and incorporated into the peptidomimetic by an α-alkylation, hydrolysis and intramolecular cyclization sequence. Further transformations on solid-phase provide access to a variety of piperazine derivatives representing a class of molecules known to exhibit central nervous system activity. The procedure works well with proline cores, but with larger six- and seven-membered ring homologues the nature of the carboxylic acid acylating the cyclic amine can lead to side reactions and result in poor overall yields.

  10. Determination of arsenic and selenium by hydride generation and headspace solid phase microextraction coupled with optical emission spectrometry

    Tyburska, Anna; Jankowski, Krzysztof, E-mail:; Rodzik, Agnieszka


    A hydride generation headspace solid phase microextraction technique has been developed in combination with optical emission spectrometry for determination of total arsenic and selenium. Hydrides were generated in a 10 mL volume septum-sealed vial and subsequently collected onto a polydimethylsiloxane/Carboxen solid phase microextraction fiber from the headspace of sample solution. After completion of the sorption, the fiber was transferred into a thermal desorption unit and the analytes were vaporized and directly introduced into argon inductively coupled plasma or helium microwave induced plasma radiation source. Experimental conditions of hydride formation reaction as well as sorption and desorption of analytes have been optimized showing the significant effect of the type of the solid phase microextraction fiber coating, the sorption time and hydrochloric acid concentration of the sample solution on analytical characteristics of the method developed. The limits of detection of arsenic and selenium were 0.1 and 0.8 ng mL{sup -1}, respectively. The limit of detection of selenium could be improved further using biosorption with baker's yeast Saccharomyces cerevisiae for analyte preconcentration. The technique was applied for the determination of total As and Se in real samples.

  11. Application of cyclic partial phase transformations for identifying kinetic transitions during solid-state phase transformations: Experiments and modeling

    Chen Hao, E-mail: [Faculty of Aerospace Engineering, Delft University of Technology, Kluyverweg 1, 2629 HS Delft (Netherlands); Appolaire, Benoit [LEM, CNRS/ONERA, 29 Av. Division Leclerc, BP 72, F-92322 Chatillon Cedex (France); Zwaag, Sybrand van der [Faculty of Aerospace Engineering, Delft University of Technology, Kluyverweg 1, 2629 HS Delft (Netherlands)


    A series of cyclic partial phase transformation experiments has been performed to investigate the growth kinetics of the austenite to ferrite phase transformation, and vice versa, in Fe-Mn-C alloys. Unlike the usual phase transformation experiments (100% parent phase {yields} 100% new phase), in the case of cyclic partial transformations two special stages are observed: a stagnant stage in which the degree of transformation does not vary while the temperature changes, and an inverse phase transformation stage, during which the phase transformation proceeds in a direction contradictory to the temperature change. The experimental results have been analyzed using paraequilibrium and local equilibrium diffusional growth models. Only the local equilibrium model was shown to predict the new features of the cyclic phase transformation kinetics. The stagnant stage was found to be due to Mn partitioning, while the inverse phase transformation is caused by non-equilibrium conditions when switching from cooling to heating and vice versa.

  12. Solid phase fermentation of Helianthus tuberosus for ethanol

    Baerwald, G.; Hamad, S.H.


    The direct fermentation of pure inulin and hammer mill crushed Helianthus tuberosus tubers (topinambur, Jerusalem artichoke) was studied using two heat-tolerant yeasts, namely Kluyveromyces marxianus and Candida kefyr. A Saccharomyces cerevisiae was included in the study so as to compare the yields of these two yeasts with that of a commercial distiller's yeast. The inulin fermentation was carried out in an 18-L bioreactor using the fed-batch and the batch-fermentation methods. The final ethanol concentration was 6.1% (L/L) which represents 82% of the theoretical yield. Commercial scale experiments with hammer mill crushed tubers gave yields lower than those found in the laboratory: 69% of the theoretical yield for direct fermentation without enzyme addition, and about 91% when cellolytic enzymes were added.

  13. Binary Solid-Liquid Phase Diagram of Phenol and t-Butanol: An Undergraduate Physical Chemistry Experiment

    Xu, Xinhua; Wang, Xiaogang; Wu, Meifen


    The determination of the solid-liquid phase diagram of a binary system is always used as an experiment in the undergraduate physical chemistry laboratory courses. However, most phase diagrams investigated in the lab are simple eutectic ones, despite the fact that complex binary solid-liquid phase diagrams are more common. In this article, the…

  14. Binary Solid-Liquid Phase Diagram of Phenol and t-Butanol: An Undergraduate Physical Chemistry Experiment

    Xu, Xinhua; Wang, Xiaogang; Wu, Meifen


    The determination of the solid-liquid phase diagram of a binary system is always used as an experiment in the undergraduate physical chemistry laboratory courses. However, most phase diagrams investigated in the lab are simple eutectic ones, despite the fact that complex binary solid-liquid phase diagrams are more common. In this article, the…

  15. Contribution to the study of the behaviour of solid particles in a confined turbulent flow using direct numerical simulation; Contribution a l'etude du comportement de particules solides en ecoulement turbulent confine par simulation numerique directe

    Rambaud, P.


    also directly used for non-homogeneous and non-isotropic turbulence. In our study, we are checking the relevance of such a direct application. At this purpose, on the half-channel, all the moving Eulerian integral times and the fluid Lagrangian integral times are computed in order to estimate the integral times of the turbulence seen. These valuations are compared with the direct computations of the integral times of the turbulence seen thanks to the Lagrangian tracking of a huge number of particles. Besides the dispersion study, this code is also presented in a configuration allowing to deal with dispersed flow with no more passive but active particles on the turbulence. The invariant of the simulation being the Reynolds number based on the bulk velocity, a forcing scheme keeping the overall flow rate is used. In spite of the validation of this scheme in single phase turbulence, it is not yet able to work efficiently in vertical turbulent downward or upward coupled two-phase flows. This problem is not met in weightlessness state, for which the macroscopic effects on the turbulence due to the solid particles are presented. (authors)

  16. Solid-Phase Capture of Proteins, Spores, and Bacteria†

    Weimer, B.C.; Walsh, M. K.; Beer, C.; Koka, R.; X. Wang


    Current methods for the detection of pathogens in food and water samples generally require a preenrichment step that allows selective enrichment of the test organism. The objective of this research was to eliminate an enrichment step to allow detection of bacteria directly in food and water samples in 30 min. A high-flow-rate, fluidized bed to capture and concentrate large (bacteria and spores) and small (protein) molecules was developed. This format, ImmunoFlow, is volume independent and use...

  17. Preparation of Plutonium Counting Source Using Solid Phase Extraction Disk

    SUN; Hong-qing; YANG; Su-liang; DING; You-qian; YANG; Jin-ling; MAO; Guo-shu


    For the determination of trace amount of plutonium,Pu(Ⅳ)may be extracted from dilute nitric acid by TTA-xylene,and stripped by concentrated nitric acid.But the small volume of strip solution used in traditional counting source preparation by direct evaporation could lead to a rather high detection limit.Plutonium in strip solution may all be absorbed on the surface of an anion exchange resin disk.And

  18. Extraction of Pb2+ using Silica from Rice Husks Ash (RHA – Chitosan as Solid Phase

    Hanandayu Widwiastuti


    Full Text Available The existence of lead (Pb compounds in waters can be caused of waste pollution from industrial activities such as dye and battery industries. Lead has toxic characteristic and is able to causing deseases. The levels of Cr(VI can be decreased by methods such as electroplating, oxidation, reduction, and membrane separation. But this methods require high cost and produce a lot of waste. Furthermore, those methods cannot determine the small concentration of Pb2+. Therefore, solid phase extraction is used because it’s a simple method and can be used to preconcentrate Pb2+ ion. The aim of this study is to create solid phase from nature material as an alternative method to determine Pb2+ in water samples. The solid phase is silica from rice husks ash (RHA that was modified using chitosan. To achieve that aim, the optimization of silica : chitosan composition was done. The influence of Pb2+ concentration and citric acid concentration was studied to obtain optimum recovery of Pb2+. Interaction between Pb2+ ion and solid phase silica – chitosan could be estimated based on the result. The result showed the optimum composition of silica : chitosan is 65% silica : 35% chitosan with Cation Exchange Capacity (CEC 0.00455 mek/g. Mass Adsorbed Pb2+for 1 g silica : chitosan 65% is 9.715 mg/g. Optimum recovery of Pb2+ on solid phase extraction is reached at concentration of Pb2+ 10 ppm and citric acid concentration 0.05 M (88.25 % and 81.18 %. This result showed that solid phase extraction using silica – chitosan can be used as an alternative method to determine Pb2+ in water.

  19. A photolabile linker for the solid-phase synthesis of peptide hydrazides and heterocycles.

    Qvortrup, Katrine; Komnatnyy, Vitaly V; Nielsen, Thomas E


    A photolabile hydrazine linker for the solid-phase synthesis of peptide hydrazides and hydrazine-derived heterocycles is presented. The developed protocols enable the efficient synthesis of structurally diverse peptide hydrazides derived from the standard amino acids, including those with side-chain protected residues at the C-terminal of the resulting peptide hydrazide, and are useful for the synthesis of dihydropyrano[2,3-c]pyrazoles. The linker is compatible with most commonly used coupling reagents and protecting groups for solid-phase peptide synthesis.

  20. Development of orthogonally protected hypusine for solid-phase peptide synthesis.

    Song, Aimin; Tom, Jeffrey; Yu, Zhiyong; Pham, Victoria; Tan, Dajin; Zhang, Dengxiong; Fang, Guoyong; Yu, Tao; Deshayes, Kurt


    An orthogonally protected hypusine reagent was developed for solid-phase synthesis of hypusinated peptides using the Fmoc/t-Bu protection strategy. The reagent was synthesized in an overall yield of 27% after seven steps from Cbz-Lys-OBzl and (R)-3-hydroxypyrrolidin-2-one. The side-chain protecting groups (Boc and t-Bu) are fully compatible with standard Fmoc chemistry and can be readily removed during the peptide cleavage step. The utility of the reagent was demonstrated by solid-phase synthesis of hypusinated peptides.

  1. Synthesis of indium tin oxide powder by solid-phase reaction with microwave heating

    Fukui, Kunihiro; Kanayama, Keiji; Katoh, Manabu; Yamamoto, Tetsuya; Yoshida, Hideto


    Indium tin oxide (ITO) powder was synthesized from indium oxide and tin oxide powders by a solid-phase method using microwave heating and conventional heating methods. Microwave heating could reduce the treatment time necessary for the completion of the solid-phase reaction by 1/30. This decrease was attributed to an increase in the diffusion rate of Sn at the local heat spot in the indium oxide formed by microwave irradiation. However, microwave heating also decreased the amount of ITO produ...

  2. Detection of ibuprofen and ciprofloxacin by solid-phase extraction and UV/Vis spectroscopy

    Zhou, Zhengwei; Jiang, Jia Qian


    A simple and economic solid-phase extraction coupled with UV/Vis spectrophotometric method is described for the analysis of ibuprofen and ciprofloxacin. Following solid-phase extraction from model wastewater samples containing standard ibuprofen or ciprofloxacin, elutes were analyzed by a UV/Vis spectrophotometer at 225 nm for ibuprofen and 280 nm for ciprofloxacin. The assay was linear for both compounds with good coefficients of correlation. This method shows good recoveries for both compounds with 101.0 ± 9.8% for ibuprofen and 99.4 ± 11.8% ciprofloxacin.

  3. A Photolabile Linker for the Solid-Phase Synthesis of Peptide Hydrazides and Heterocycles

    Qvortrup, Katrine; Komnatnyy, Vitaly V.; Nielsen, Thomas Eiland


    A photolabile hydrazine linker for the solid-phase synthesis of peptide hydrazides and hydrazine-derived heterocycles is presented. The developed protocols enable the efficient synthesis of structurally diverse peptide hydrazides derived from the standard amino adds, including those with side-cha......-chain protected residues at the C-terminal of the resulting peptide hydrazide, and are useful for the synthesis of dihydropyrano[2,3-c]pyrazoles. The linker is compatible with most commonly used coupling reagents and protecting groups for solid-phase peptide synthesis....

  4. CuAAC: An Efficient Click Chemistry Reaction on Solid Phase.

    Castro, Vida; Rodríguez, Hortensia; Albericio, Fernando


    Click chemistry is an approach that uses efficient and reliable reactions, such as Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC), to bind two molecular building blocks. CuAAC has broad applications in medicinal chemistry and other fields of chemistry. This review describes the general features and applications of CuAAC in solid-phase synthesis (CuAAC-SP), highlighting the suitability of this kind of reaction for peptides, nucleotides, small molecules, supramolecular structures, and polymers, among others. This versatile reaction is expected to become pivotal for meeting future challenges in solid-phase chemistry.

  5. Adaptive compensation of a direct liquid-cooled solid-state MOPA system

    Dong, Lizhi; Chen, Shanqiu; Chen, Xiaojun; Liu, Wenjin; Hu, Ke; Lai, Boheng; Yang, Ping; Wang, Shuai; He, Xing; Xu, Bing; Liu, Le; Liu, Yang; Wang, Zhe; Wang, Gang


    Direct liquid-cooling is a promising way of power scaling and heat management for solid-state lasers. A side-pumped direct liquid-cooled solid-state pulsed zigzag MOPA system is established based on this advanced concept. However, its beam quality is degraded by the thermal distortions in the non-zigzag direction and the flowing coolant. We develop an adaptive optics system to improve its beam quality, which primarily includes a low-order aberration compensator and a 59-actuator deformable mirror. The beam is first corrected by the low-order aberration compensator to remove large defocus and astigmatism, and its size is reshaped simultaneously to fulfill the demands of applications. Then the beam is further corrected by the deformable mirror. With collaborative operation of the low-order aberration compensator and the deformable mirror, we have achieved average beam quality of β=2.8.

  6. Modelling of solid polymer and direct methanol fuel cells: Phenomenological equations and analytical solutions

    Kauranen, P. S.


    In the solid state concept of a direct methanol fuel cell (DMFC), methanol is directly oxidized at the anode of a solid polymer electrolyte fuel cell (SPEFC). Mathematical modelling of the transport and reaction phenomena within the electrodes and the electrolyte membrane is needed in order to get a closer insight into the operation of the fuel cell. In the work, macro-homogenous porous electrode and dilute solution theories are used to derive the phenomenological equations describing the transport and reaction mechanisms in a SPEFC single cell. The equations are first derived for a conventional H2/air SPEFC, and then extended for a DMFC. The basic model is derived in a one dimensional form in which it is assumed that species transport take place only in the direction crossing the cell sandwich. In addition, two dimensional descriptions of the catalyst layer are reviewed.

  7. A solid-phase blocking ELISA for detection of type O foot-and-mouth disease virus antibodies suitable for mass serology.

    Chenard, G.; Miedema, K.; Moonen, P.; Schrijver, R.S.; Dekker, A.


    A simple solid-phase blocking ELISA for the detection of antibodies directed against type O foot-and-mouth disease virus (FMDV) was developed. The ELISA was validated using field sera collected from cattle, pigs and sheep originating from FMDV infected and non-infected Dutch farms, reference sera ob

  8. Novel functionalized polymeric fabric and fiber material as solid support for solid-phase synthesis and biomedical applications

    Xiang, Bei

    The aim of the research is to develop novel polymer solid support by modifying or fabricating polymeric fibrous materials for peptide synthesis and biomedical applications. Originally chemical inert isotactic polypropylene (iPP) fabric was utilized and modified to serve as a functional flexible planar solid support for solid phase peptide synthesis. The modification was achieved through thermal initiated radical grafting polymerization using acrylic acid, poly (ethylene glycol) diacrylate as monomers, and benzoyl peroxide as radical initiator. The iPP fabric was successfully functionalized and possessing as high as 0.7mmol/g carboxylic acid groups. Peptide ligand LHPQF was successfully synthesized on the new functional planar support. Specific enzyme immobilization was fulfilled on the functional iPP fabric support. A commercially available ethylene-acrylic acid copolymer was made into ultrafine copolymer fiber bundles which are composed of nanofibers with diameters ranging from 200nm to 800nm. Various mixing ratios of copolymer/matrix materials were utilized to explore the effect on the final nanofiber physical properties including morphology and stability in solvents. The surface carboxylic acid groups were further converted to amino groups before the functional nanofibers can be applied in solid phase peptide synthesis. Two peptide ligands, LHPQF and HWRGWV, were also successfully synthesized on the nanofiber bundles. Streptavidin and human immunoglobulin G specific binding with the corresponding ligand which was anchored on the nanofibers was conducted successfully to illustrate the potential applications of the nanofiber materials in biomedical field. Further study on the dispersion of the ethylene-acrylic acid nanofiber bundles was pursued to take advantage of the super high active surface area of functional nanofibers. To manipulate the polymer nanofibers during synthesis and bio-assays, a technique was developed to controllably assemble and disperse the

  9. Temperature Effects on the Wind Direction Measurement of 2D Solid Thermal Wind Sensors

    Bei Chen


    Full Text Available For a two-dimensional solid silicon thermal wind sensor with symmetrical structure, the wind speed and direction information can be derived from the output voltages in two orthogonal directions, i.e., the north-south and east-west. However, the output voltages in these two directions will vary linearly with the ambient temperature. Therefore, in this paper, a temperature model to study the temperature effect on the wind direction measurement has been developed. A theoretical analysis has been presented first, and then Finite Element Method (FEM simulations have been performed. It is found that due to symmetrical structure of the thermal wind sensor, the temperature effects on the output signals in the north-south and east-west directions are highly similar. As a result, the wind direction measurement of the thermal wind sensor is approximately independent of the ambient temperature. The experimental results fit the theoretical analysis and simulation results very well.

  10. Temperature Effects on the Wind Direction Measurement of 2D Solid Thermal Wind Sensors.

    Chen, Bei; Zhu, Yan-Qing; Yi, Zhenxiang; Qin, Ming; Huang, Qing-An


    For a two-dimensional solid silicon thermal wind sensor with symmetrical structure, the wind speed and direction information can be derived from the output voltages in two orthogonal directions, i.e., the north-south and east-west. However, the output voltages in these two directions will vary linearly with the ambient temperature. Therefore, in this paper, a temperature model to study the temperature effect on the wind direction measurement has been developed. A theoretical analysis has been presented first, and then Finite Element Method (FEM) simulations have been performed. It is found that due to symmetrical structure of the thermal wind sensor, the temperature effects on the output signals in the north-south and east-west directions are highly similar. As a result, the wind direction measurement of the thermal wind sensor is approximately independent of the ambient temperature. The experimental results fit the theoretical analysis and simulation results very well.

  11. Liquid-phase extraction coupled with metal-organic frameworks-based dispersive solid phase extraction of herbicides in peanuts.

    Li, Na; Wang, Zhibing; Zhang, Liyuan; Nian, Li; Lei, Lei; Yang, Xiao; Zhang, Hanqi; Yu, Aimin


    Liquid-phase extraction coupled with metal-organic frameworks-based dispersive solid phase extraction was developed and applied to the extraction of pesticides in high fatty matrices. The herbicides were ultrasonically extracted from peanut using ethyl acetate as extraction solvent. The separation of the analytes from a large amount of co-extractive fat was achieved by dispersive solid-phase extraction using MIL-101(Cr) as sorbent. In this step, the analytes were adsorbed on MIL-101(Cr) and the fat remained in bulk. The herbicides were separated and determined by high-performance liquid chromatography. The experimental parameters, including type and volume of extraction solvent, ultrasonication time, volume of hexane and eluting solvent, amount of MIL-101(Cr) and dispersive solid phase extraction time, were optimized. The limits of detection for herbicides range from 0.98 to 1.9 μg/kg. The recoveries of the herbicides are in the range of 89.5-102.7% and relative standard deviations are equal or lower than 7.0%. The proposed method is simple, effective and suitable for treatment of the samples containing high content of fat.

  12. Recent developments and future trends in solid phase microextraction techniques towards green analytical chemistry.

    Spietelun, Agata; Marcinkowski, Łukasz; de la Guardia, Miguel; Namieśnik, Jacek


    Solid phase microextraction find increasing applications in the sample preparation step before chromatographic determination of analytes in samples with a complex composition. These techniques allow for integrating several operations, such as sample collection, extraction, analyte enrichment above the detection limit of a given measuring instrument and the isolation of analytes from sample matrix. In this work the information about novel methodological and instrumental solutions in relation to different variants of solid phase extraction techniques, solid-phase microextraction (SPME), stir bar sorptive extraction (SBSE) and magnetic solid phase extraction (MSPE) is presented, including practical applications of these techniques and a critical discussion about their advantages and disadvantages. The proposed solutions fulfill the requirements resulting from the concept of sustainable development, and specifically from the implementation of green chemistry principles in analytical laboratories. Therefore, particular attention was paid to the description of possible uses of novel, selective stationary phases in extraction techniques, inter alia, polymeric ionic liquids, carbon nanotubes, and silica- and carbon-based sorbents. The methodological solutions, together with properly matched sampling devices for collecting analytes from samples with varying matrix composition, enable us to reduce the number of errors during the sample preparation prior to chromatographic analysis as well as to limit the negative impact of this analytical step on the natural environment and the health of laboratory employees.

  13. Solid solution and amorphous phase in Ti–Nb–Ta–Mn systems synthesized by mechanical alloying

    Aguilar, C., E-mail: [Departamento de Ingeniería Metalúrgica y Materiales, Universidad Técnica Federico Santa María, Av. España 1680, Valparaíso (Chile); Guzman, P. [Departamento de Ingeniería Metalúrgica y Materiales, Universidad Técnica Federico Santa María, Av. España 1680, Valparaíso (Chile); Lascano, S. [Departamento de Ingeniería Mecánica, Universidad Técnica Federico Santa María, Av. España 1680, Valparaíso (Chile); Parra, C. [Departamento de Física, Universidad Técnica Federico Santa María, Av. España 1680, Valparaíso (Chile); Bejar, L. [Instituto de Investigaciones Metalúrgicas, Universidad Michoacana de San Nicolás de Hidalgo, Ciudad Universitaria, Morelia C.P. 58000, Michoacán (Mexico); Medina, A. [Facultad de Ingeniería Mecánica, Universidad Michoacana de San Nicolás de Hidalgo, Ciudad Universitaria, C.P. 58000, Michoacán (Mexico); Guzman, D. [Departamento de Metalurgia, Universidad de Atacama, Av. España 485, Copiapó (Chile)


    This work discusses the formation of Ti–30Nb–13Ta–xMn (x: 2, 4 and 6 wt%) solid solution by mechanical alloying using a shaker mill. A solid solution was formed after 15 h of milling and an amorphous phase was formed after 30 h of milling, according to X-ray diffraction results. Disappearance of strongest X-ray diffraction peaks of Nb, Ta and Mn indicated the formation of solid solution, while, X-ray diffraction patterns of powders milled for 30 h showed an amorphous hump with crystalline peaks in the angular range of 35–45° in 2θ. TEM image analysis showed the presence of nanocrystalline intermetallic compounds embedded in an amorphous matrix. Mn{sub 2}Ti, MnTi and NbTi{sub 4} intermetallic compounds were detected and revealed crystallites with size ranging from 3 to 20 nm. The Gibbs free energy for the formation of solid solution and amorphous phase of three ternary systems (Ti–Nb–Ta, Ti–Nb–Mn and Ti–Ta–Mn) was calculated using extended Miedema's model. Experimental and thermodynamic data confirmed that solid solution was first formed in the alloy with 6wt% Mn followed by the formation of an amorphous phase as milling time increases. The presence of Mn promoted the formation of amorphous phase because the atomic radius difference between Mn with Ti, Nb and Ta. - Highlights: • Thermodynamics analysis of extension of solid solution of the Ti–Nb–Ta–Mn system. • Formation of amorphous phase and intermetallic compounds were observed. • Nanocrystalline intermetallic compounds were formed with the sizes between 3 and 20 nm.

  14. Optical manipulation of Berry phase in a solid-state spin qubit

    Yale, Christopher G; Zhou, Brian B; Auer, Adrian; Burkard, Guido; Awschalom, David D


    The phase relation between quantum states represents an essential resource for the storage and processing of quantum information. While quantum phases are commonly controlled dynamically by tuning energetic interactions, utilizing geometric phases that accumulate during cyclic evolution may offer superior robustness to noise. To date, demonstrations of geometric phase control in solid-state systems rely on microwave fields that have limited spatial resolution. Here, we demonstrate an all-optical method based on stimulated Raman adiabatic passage to accumulate a geometric phase, the Berry phase, in an individual nitrogen-vacancy (NV) center in diamond. Using diffraction-limited laser light, we guide the NV center's spin along loops on the Bloch sphere to enclose arbitrary Berry phase and characterize these trajectories through time-resolved state tomography. We investigate the limits of this control due to loss of adiabiaticity and decoherence, as well as its robustness to noise intentionally introduced into t...

  15. Bioproduction of benzaldehyde in a solid-liquid two-phase partitioning bioreactor using Pichia pastoris.

    Jain, Ashu N; Khan, Tanya R; Daugulis, Andrew J


    The bioproduction of benzaldehyde from benzyl alcohol using Pichia pastoris was examined in a solid-liquid two-phase partitioning bioreactor (TPPB) to reduce substrate and product inhibition. Rational polymer selection identified Elvax 40W as an effective sequestering phase, possessing partition coefficients for benzyl alcohol and benzaldehyde of 3.5 and 35.4, respectively. The use of Elvax 40W increased the overall mass of benzaldehyde produced by approx. 300% in a 5 l bioreactor, relative to a single phase biotransformation. The two-phase system had a molar yield of 0.99, indicating that only minor losses occurred. These results provide a promising starting point for solid-liquid TPPBs to enhance benzaldehyde production, and suggest that multiple, targeted polymers may provide relief for transformations characterized by multiple inhibitory substrates/product/by-products.

  16. AWESoMe: A code for the calculation of phase and group velocities of acoustic waves in homogeneous solids

    Muñoz-Santiburcio, Daniel; Hernández-Laguna, Alfonso; Soto, Juan I.


    We present AWESoMe, an implementation of a method for the evaluation of acoustic wave velocities in homogeneous solid media. The code computes the phase and group velocities for all the possible propagation directions, as well as some related parameters such as the polarization vectors, the power flow angle and the enhancement factor. The code is conveniently interfaced with GNUPLOT, thus offering immediate visualization of the results. AWESoMe is open-source software, available under the GNU General Public License v3.

  17. Two novel silicon phases with direct band gaps.

    Fan, Qingyang; Chai, Changchun; Wei, Qun; Yang, Yintang


    Due to its abundance, silicon is the preferred solar-cell material despite the fact that many silicon allotropes have indirect band gaps. Elemental silicon has a large impact on the economy of the modern world and is of fundamental importance in the technological field, particularly in the solar cell industry. Looking for direct band gap silicon is still an important field in material science. Based on density function theory with the ultrasoft pseudopotential scheme in the frame of the local density approximation and the generalized gradient approximation, we have systematically studied the structural stability, absorption spectra, electronic, optical and mechanical properties and minimum thermal conductivity of two novel silicon phases, Cm-32 silicon and P21/m silicon. These are both thermally, dynamically and mechanically stable. The absorption spectra of Cm-32 silicon and P21/m silicon exhibit significant overlap with the solar spectrum and thus, excellent photovoltaic efficiency with great improvements over Fd3[combining macron]m Si. These two novel Si structures with direct band gaps could be applied in single p-n junction thin-film solar cells or tandem photovoltaic devices.

  18. Homogenization of. beta. -solid solution during fast heating of two-phase titanium alloys

    Gridnev, V.N.; Zhuravlev, A.F.; Zhuravlev, B.F.; Ivasishin, O.M.; Markovskij, P.E. (AN Ukrainskoj SSR, Kiev. Inst. Metallofiziki)


    Using model alloy Ti-10%Mo as an example the homogenization of high-temperature ..beta..-phase during fast heating has been studied by calculational and experimental methods. The effect of heating rate and the initial structure disoersion on the homogenization is shown. A method is suggested for evaluation of the concentration state of ..beta..-solid solution depleted parts of commercial two-phase titanium alloys. The method has been used to study the homogenization process.

  19. Numerical investigation of confined swirling gas-solid two phase jet


    This paper presents a k-ε-kp multi-fluid model for simulating confined swirling gas-solid two phase jet comprised of particle-laden flow from a center tube and a swirling air stream entering the test section from the coaxial annular. A series of numerical simulations of the two-phase flow of 30 μm, 45 μm, 60 μm diameter particles respectively yielded results fitting well with published experimental data.

  20. Numerical Simulation of Swirling Gas-solid Two Phase Flow through a Pipe Expansion

    Jin Hanhui; Xia Jun; Fan Jianren; Cen Kefa


    A k- ε -kp multi-fluid model is stated and adopted to simulate swirling gas-solid two phase flow. A particle-laden flow from a center tube and a swirling air stream from the coaxial annular enter the test section. A series of numerical simulations of the two-phase flow are performed based on 30 μ m, 45 μ m, 60 μ m diameter particles respectively. The results fit well with published experimental data.

  1. Numerical investigation of confined swirling gas-solid two phase jet

    金晗辉; 夏钧; 樊建人; 岑可法


    This paper presents a k-e-kp multi-fluid model for simulating confined swirling gas-solid two phase jet comprised of particle-laden flow from a center tube and a swirling air stream entering the test section from the coaxial annular. A series of numerical simulations of the two-phase flow of 30μm, 45μm, 60μm diameter particles respectively yielded results fitting well with published experimental data.


    S. Manna


    Full Text Available High performance liquid chromatographic determination of organophosphorous compound has been done by reverse phase chromatography in goats. The goats were dying showing the symptoms of organophosphorous poisoning. The viscera and stomach contents sample were received from Project Co-Ordinator, Animal Disease Research Institute, Phulnakhara, Cuttack, Orissa. The analysis of samples by HPLC with UV detector after cleaning up in Solid Phase Extraction (SPE revealed presence of malathion that was later quantified.

  3. The 2D Alternative Binary L-J System: Solid-Liquid Phase Diagram

    ZHANG Zhi; CHEN Li-Rong


    The Lennard-Jones potential is introduced into the Collins model and is generalized to the two-dimensionalalternative binary system. The Gibbs free energy of the binary system is calculated. According to the thermodynamicconditions of solid-liquid equilibrium, the "cigar-type" phase diagram and the phase diagram with a minimum areobtained. The results are quite analogous to the behavior of three-dimensional substances.

  4. The Solid Phase Curing Time Effect of Asbuton with Texapon Emulsifier at the Optimum Bitumen Content

    Sarwono, D.; Surya D, R.; Setyawan, A.; Djumari


    Buton asphalt (asbuton) could not be utilized optimally in Indonesia. Asbuton utilization rate was still low because the processed product of asbuton still have impracticable form in the term of use and also requiring high processing costs. This research aimed to obtain asphalt products from asbuton practical for be used through the extraction process and not requiring expensive processing cost. This research was done with experimental method in laboratory. The composition of emulsify asbuton were 5/20 grain, premium, texapon, HCl, and aquades. Solid phase was the mixture asbuton 5/20 grain and premium with 3 minutes mixing time. Liquid phase consisted texapon, HCl and aquades. The aging process was done after solid phase mixing process in order to reaction and tie of solid phase mixed become more optimal for high solubility level of asphalt production. Aging variable time were 30, 60, 90, 120, and 150 minutes. Solid and liquid phase was mixed for emulsify asbuton production, then extracted for 25 minutes. Solubility level of asphalt, water level, and asphalt characteristic was tested at extraction result of emulsify asbuton with most optimum ashphal level. The result of analysis tested data asphalt solubility level at extract asbuton resulted 94.77% on 120 minutes aging variable time. Water level test resulted water content reduction on emulsify asbuton more long time on occurring of aging solid phase. Examination of asphalt characteristic at extraction result of emulsify asbuton with optimum asphalt solubility level, obtain specimen that have rigid and strong texture in order that examination result have not sufficient ductility and penetration value.

  5. Reflection at a liquid-solid interface of a transient ultrasonic field radiated by a linear phased array transducer.

    Maghlaoui, Nadir; Belgroune, Djema; Ourak, Mohamed; Djelouah, Hakim


    In order to put in evidence the specular reflection and the non-specular reflection in the transient case, we have used a model for the study of the transient ultrasonic waves radiated by a linear phased array transducer in a liquid and reflected by a solid plane interface. This method is an extension of the angular spectrum method to the transient case where the reflection at the plane interface is taken into account by using the reflection coefficient for harmonic plane waves. The results obtained highlighted the different components of the ultrasonic field: the direct and edge waves as well as the longitudinal head waves or leaky Rayleigh waves. The transient representation of these waves have been carefully analyzed and discussed by the rays model. Instantaneous cartographies allowed a clear description of all the waves which appear at the liquid-solid interface. The obtained results have been compared to those obtained with a finite element method package.

  6. Direct Succinic Acid Production from Minimally Pretreated Biomass Using Sequential Solid-State and Slurry Fermentation with Mixed Fungal Cultures

    Jerico Alcantara


    Full Text Available Conventional bio-based succinic acid production involves anaerobic bacterial fermentation of pure sugars. This study explored a new route for directly producing succinic acid from minimally-pretreated lignocellulosic biomass via a consolidated bioprocessing technology employing a mixed lignocellulolytic and acidogenic fungal co-culture. The process involved a solid-state pre-fermentation stage followed by a two-phase slurry fermentation stage. During the solid-state pre-fermentation stage, Aspergillus niger and Trichoderma reesei were co-cultured in a nitrogen-rich substrate (e.g., soybean hull to induce cellulolytic enzyme activity. The ligninolytic fungus Phanerochaete chrysosporium was grown separately on carbon-rich birch wood chips to induce ligninolytic enzymes, rendering the biomass more susceptible to cellulase attack. The solid-state pre-cultures were then combined in a slurry fermentation culture to achieve simultaneous enzymatic cellulolysis and succinic acid production. This approach generated succinic acid at maximum titers of 32.43 g/L after 72 h of batch slurry fermentation (~10 g/L production, and 61.12 g/L after 36 h of addition of fresh birch wood chips at the onset of the slurry fermentation stage (~26 g/L production. Based on this result, this approach is a promising alternative to current bacterial succinic acid production due to its minimal substrate pretreatment requirements, which could reduce production costs.

  7. The Effects of Solid Phase Additives on Sintering Properties of Alumina Bioceramic

    WANG Xin-yu; LI Shi-pu; HE Jian-hua; JIANG Xin; LI Jian-hua


    In order to reduce the sintering temperature and improve the preparing conditions of alumina bioceramics,the Mg-Zr-Y composite solid phase additives were added into high purity Al2O3 micro-powder by chemical coprecipitation method.The powder was shaped under 200MPa cold isostatic pressure,and then the biscuits were sintered at 1600℃ under normal pressure.The sintered alumina materials were tested and the sintering mechanism was discussed.The results show that physical properties of the material were improved comparatively.The Mg-Zr-Y composite solid additives could promote the sintering of alumina bioceramics and the mechanism is solid phase sintering.

  8. Advances in automatic, manual and microwave-assisted solid-phase peptide synthesis.

    Sabatino, Giuseppina; Papini, Anna M


    Solid-phase strategies speed up the production of both short- and long-sequence peptides compared with solution methodologies. Therefore, solid-phase peptide synthesis (SPPS), proposed by Merrifield in the early 1960s, contributed to the 'Peptide Revolution' in the fields of diagnostics, and drug and vaccine development. Since then, peptide chemistry research has aimed to optimize these synthetic procedures, focusing on areas such as amide bond formation (the coupling step), solid supports and automation. Particular attention was devoted to the environmental impact of SPPS: the requirement for large amounts of organic solvents meant high costs for industrial peptide manufacturing that needed to be reduced. SPPS, alone or in hybrid technologies, has become strategic for the production of peptides as active pharmaceutical ingredients on a commercial scale.

  9. The synthesis and chemical durability of Nd-doped single-phase zirconolite solid solutions

    Cai, Xin; Teng, Yuancheng; Wu, Lang; Zhang, Kuibao; Huang, Yi


    Nd-doped single-phase zirconolite solid solutions was synthesized by solid-state reaction and following two steps of acid treatment. The phase composition, microstructure, and chemical durability of the zirconolite solid solutions were investigated. About 15 at% Nd was successfully stabilized into the zirconolite. The element mapping images of Ca, Zr, Nd and Ti show that all the elements are almost distributed homogeneously in the zirconolite waste forms. Product Consistency Test (PCT) was conducted under different pH values (pH = 5, 7 and 9) to evaluate the chemical durability of the Nd-doped zirconolite waste forms. The normalized element release rate of Ca (LRCa) in pH = 5 medium is higher than that of pH = 7 and 9, while the LRNd value remains almost unchanged under different pH values. The LRNd value is as low as 10-5 g m-2 d-1 after 42 days.

  10. Soxhlet-assisted matrix solid phase dispersion to extract flavonoids from rape (Brassica campestris) bee pollen.

    Ma, Shuangqin; Tu, Xijuan; Dong, Jiangtao; Long, Peng; Yang, Wenchao; Miao, Xiaoqing; Chen, Wenbin; Wu, Zhenhong


    Soxhlet-assisted matrix solid phase dispersion (SA-MSPD) method was developed to extract flavonoids from rape (Brassica campestris) bee pollen. Extraction parameters including the extraction solvent, the extraction time, and the solid support conditions were investigated and optimized. The best extraction yields were obtained using ethanol as the extraction solvent, silica gel as the solid support with 1:2 samples to solid support ratio, and the extraction time of one hour. Comparing with the conventional solvent extraction and Soxhlet method, our results show that SA-MSPD method is a more effective technique with clean-up ability. In the test of six different samples of rape bee pollen, the extracted content of flavonoids was close to 10mg/g. The present work provided a simple and effective method for extracting flavonoids from rape bee pollen, and it could be applied in the studies of other kinds of bee pollen.

  11. Understanding processing-induced phase transformations in erythromycin-PEG 6000 solid dispersions

    Mirza, Sabiruddin; Heinämäki, Jyrki; Miroshnyk, Inna


    Since the quality and performance of a pharmaceutical solid formulation depend on solid state of the drug and excipients, a thorough investigation of potential processing-induced transformations (PITs) of the ingredients is required. In this study, the physical phenomena taking place during...... formulation of erythromycin (EM) dihydrate solid dispersions with polyethylene glycol (PEG) 6000 by melting were investigated. PITs were monitored in situ using variable temperature X-ray powder diffraction (VT-XRPD), differential scanning calorimetry (DSC), and hot-stage microscopy (HSM). Possible...... intermolecular interactions between the drug and polymer in the solid state were further studied by Fourier transform infrared (FTIR) spectroscopy. While in the absence of PEG the dehydration was the only transformation observed, hot-melt processing with the polymer caused the drug to undergo multiple phase...

  12. Ni coarsening in the three-phase solid oxide fuel cell anode - a phase-field simulation study

    Chen, Hsun-Yi; Cronin, J Scott; Wilson, James R; Barnett, Scott A; Thornton, Katsuyo


    Ni coarsening in Ni-yttria stabilized zirconia (YSZ) solid oxide fuel cell anodes is considered a major reason for anode degradation. We present a predictive, quantative modeling framework based on the phase-field approach to systematically examine coarsening kinetics in such anodes. The initial structures for simulations are experimentally acquired functional layers of anodes. Sample size effects and error analysis of contact angles are examined. Three phase boundary (TPB) lengths and Ni surface areas are quantatively identified on the basis of the active, dead-end, and isolated phase clusters throughout coarsening. Tortuosity evolution of the pores is also investigated. We find that phase clusters with larger characteristic length evolve slower than those with smaller length scales. As a result, coarsening has small positive effects on transport, and impacts less on the active Ni surface area than the total counter part. TPBs, however, are found to be sensitive to local morphological features and are only i...

  13. Indirect solid-phase immunosorbent assay for detection of arenavirus antigens and antibodies

    Ivanov, A.P.; Rezapkin, G.V.; Dzagurova, T.K.; Tkachenko, E.A. (Institute of Poliomyelitis anU Viral Encephalities of the U.S.S.R. Academy of Medical Sciences, Moscow)


    Indirect enzyme-linked immunosorbent assay (ELISA) and solid phase radioimmunoassay (SPRIA) using either enti-human or anti-mouse IgG labelled with horseradish peroxidase and /sup 125/I, respectively, were developed for the detection of Junin, Machupo, Tacaribe, Amapari, Tamiami, Lassa and LCM arenaviruses. Both methods allow high sensitivity detection of arenavirus antigens and antibodies.

  14. Solid-phase synthesis of an apoptosis-inducing tetrapeptide mimicking the Smac protein

    Le Quement, Sebastian Thordal; Ishøy, Mette; Petersen, Mette Terp;


    An approach for the solid-phase synthesis of apoptosis-inducing Smac peptidomimetics is presented. Using a Rink linker strategy, tetrapeptides mimicking the N-4-terminal residue of the Smac protein [(N-Me)AVPF sequence] were synthesized on PEGA resin in excellent purities and yields. Following tw...

  15. Detection and specifity of class specific antibodies to whole bacteria cells using a solid phase radioimmunoassay

    Czerkinsky, C.; Rees, A.S.; Bergimeier, L.A.; Challacombe, S.J. (Guy' s Hospital Medical and Dental Schools, London (UK))


    A solid phase radioimmunoassay has been developed which can be used for the detection of isotype specific antibodies to whole bacteria and other particulate antigens, and is applicable to a variety of species. Bacteria are bound to the solid phase by the use either of antibodies, or of methyl glyoxal. Both methods result in a sensitive and reproducible assay, and bacteria do not appear to desorb from the solid phase. The specificity of antibodies to whole bacteria was examined by absorption of antisera with various species of bacteria and retesting, or by determining the binding of antisera to various bacteria bound to the solid phase. Both methods revealed specificity for the bacteria examined. Inhibition studies showed that antibodies to Streptococcus mutans whole cells could be inhibited by purified cell surface antigens glucosyltransferase and antigen I/II, but only minimally by lipoteichoic acid, c polysaccharide or dextran. In murine antisera antibodies of the IgG, IgM, and IgA classes could be detected at amounts of less than 1 ng/ml.

  16. New method for the preparation of solid-phase bound isocyanocarboxylic acids and Ugi reactions therewith

    Henkel, Bernd; Sax, Michael; Dömling, Alexander


    A novel method of synthesizing solid-phase bound isocyanocarboxylic acids is reported. The potassium salts of four different isocyanocarboxylic acids are coupled onto a brominated resin in DMF in good yields. 32 Ugi reactions were performed using these resins and 24 products were obtained in good to

  17. A Discovery-Oriented Approach to Solid-Phase Peptide Synthesis

    Bockman, Matthew R.; Miedema, Christopher J.; Brennan, Brian B.


    In this discovery-oriented laboratory experiment, students use solid-phase synthesis techniques to construct a dipeptide containing an unknown amino acid. Following synthesis and cleavage from the polymeric support, electrospray ionization-mass spectrometry is employed to identify the unknown amino acid that was used in the peptide coupling. This…

  18. Solid Phase Extraction: Applications to the Chromatographic Analysis of Vegetable Oils and Fats

    Panagiotopoulout, P. M.; Tsimidou, M.


    Applications of solid-phase extraction for the isolation of certain lipid classes prior to chromatographic analysis are given. More information was found for sterols and related compounds, polar phenols and contaminants such as polycyclic aromatic hydrocarbons. Detailed analytical protocols are presented and discussed in many cases. (Author) 120 refs.

  19. Comparison of solid and liquid-phase bioassays using ecoscores to assess contaminated soils

    Lors, Christine [Universite Lille Nord de France, 1bis rue Georges Lefevre, 59044 Lille Cedex (France); Ecole des Mines de Douai, LGCgE-MPE-GCE, 941 rue Charles-Bourseul, 59500 Douai (France); Centre National de Recherche sur les Sites et Sols Pollues, 930 Boulevard Lahure, BP 537, 59505 Douai Cedex (France); Ponge, Jean-Francois, E-mail: [Museum National d' Histoire Naturelle, Departement Ecologie et Gestion de la Biodiversite, CNRS UMR 7179, 4 Avenue du Petit-Chateau, 91800 Brunoy (France); Martinez Aldaya, Maite [Museum National d' Histoire Naturelle, Departement Ecologie et Gestion de la Biodiversite, CNRS UMR 7179, 4 Avenue du Petit-Chateau, 91800 Brunoy (France); Damidot, Denis [Universite Lille Nord de France, 1bis rue Georges Lefevre, 59044 Lille Cedex (France); Ecole des Mines de Douai, LGCgE-MPE-GCE, 941 rue Charles-Bourseul, 59500 Douai (France)


    Bioassays on aqueous and solid phases of contaminated soils were compared, belonging to a wide array of trophic and response levels and using ecoscores for evaluating ecotoxicological and genotoxicological endpoints. The method was applied to four coke factory soils contaminated mainly with PAHs, but also to a lesser extent by heavy metals and cyanides. Aquatic bioassays do not differ from terrestrial bioassays when scaling soils according to toxicity but they are complementary from the viewpoint of ecological relevance. Both aquatic and terrestrial endpoints are strongly correlated with concentrations of 3-ring PAHs. This evaluation procedure allows us to propose a cost-effective battery which embraces a wide array of test organisms and response levels: it includes two rapid bioassays (Microtox) and springtail avoidance), a micronucleus test and three bioassays of a longer duration (algal growth, lettuce germination and springtail reproduction). This battery can be recommended for a cost-effective assessment of polluted/remediated soils. - Highlights: > Comparison of liquid- and solid-phase bioassays on contaminated soils, using ecoscores. > Complementarity of liquid- and solid-phase bioassays for the evaluation of environmental hazards. > Proposal for a restricted battery of 5 most sensitive tests. > Use of this restricted battery for a cost-effective assessment of polluted/remediated soils. - Aqueous and solid phases of contaminated soils give similar results in terms of toxicity but are complementary for the evaluation of environmental hazards by ecoscores.

  20. Solid-phase synthesis of polyfunctional polylysine dendrons using aldehyde linkers

    Svenssen, Daniel K.; Mirsharghi, Sahar; Boas, Ulrik


    A straightforward method for the solid-phase synthesis of C-terminally modified polylysine dendrons has been developed by applying bisalkoxybenzaldehyde and trisalkoxybenzaldehyde linkers. The method has been used for the synthesis of polylysine dendrons with a variety of C-terminal ‘tail groups’...

  1. Solid-phase oligosaccharide synthesis with tris(alkoxy)benzyl amine (BAL) safety-catch anchoring

    Tolborg, Jakob Fjord; Jensen, Knud Jørgen


    A tris(alkoxy)benzylamine (BAL) handle strategy was developed for safety-catch anchoring of D-glucosamine derivatives in solid-phase synthesis of oligosaccharides; the linkage between the BAL handle and the amine proved stable to conc. TFA and Lewis acids, but after N-acylation the amide could...

  2. A Long Chain Alcohol as Support in Solid Phase Organic Synthesis

    Nurlela, Yeni; Minnaard, Adrian J.; Achmad, Sadijah; Wahyuningrum, Deana


    The solid phase synthesis is a method by which organic compound synthesis are performed on a support. With this method, the purification can be carried out easily by simple filtration and washing procedures. Long-chain alcohol (C-100 alcohol) can be used as a support because of its insolubility in o

  3. A Solid Phase Synthesis of Chalcones by Claisen-Schmidt Condensations


    In order to accelerate the development of relatively inexpensive antimalarials that are effective against chloroquine-resistant strains of Plasmodium falclparum, a methodology for the solid phase synthesis of chalcone (l, 3-diphenyl-2-propen-l-one) analogues in reasonably high yields has been developed.

  4. Development of a Solid Phase Extraction Method for Agricultural Pesticides in Large-Volume Water Samples

    An analytical method using solid phase extraction (SPE) and analysis by gas chromatography/mass spectrometry (GC/MS) was developed for the trace determination of a variety of agricultural pesticides and selected transformation products in large-volume high-elevation lake water sa...

  5. Microwave-assisted solid-phase Ugi four-component condensations

    Nielsen, John


    An 18-member library was constructed from 2 isocyanides, 3 aldehydes and 3 carboxylic acids via microwave-assisted solid-phase Ugi reactions on TentaGel S RAM. Products of high purity were obtained in moderate to excellent yields after reaction times of 5 minutes or less (irradiation at 60W). (C...

  6. Side-chain-anchored N(alpha)-Fmoc-Tyr-OPfp for bidirectional solid-phase synthesis

    Olsen, Christian A; Jørgensen, Malene; Hansen, Steen H;


    [reaction: see text] A mild resin-immobilization strategy employing a readily prepared trityl bromide resin for anchoring building blocks via a phenol group has been developed. With N(alpha)-Fmoc-Tyr-OPfp as a starter building block, it was possible to prepare asymmetrically substituted hybrids o...... of spider- and wasp-type polyamine toxins using solid-phase peptide synthesis conditions....

  7. Speciation analysis of aqueous nanoparticulate diclofenac complexes by solid-phase microextraction

    Zielinska, K.; Leeuwen, van H.P.; Thibault, S.; Town, R.M.


    The dynamic sorption of an organic compound by nanoparticles (NPs) is analyzed by solid-phase microextraction (SPME) for the example case of the pharmaceutical diclofenac in dispersions of impermeable (silica, SiO(2)) and permeable (bovine serum albumin, BSA) NPs. It is shown that only the protonate

  8. Solid-phase synthesis of succinylhydroxamate peptides : Functionalized matrix metalloproteinase inhibitors

    Leeuwenburgh, MA; Geurink, PP; Klein, T; Kauffman, HF; van der Marel, GA; Bischoff, R; Overkleeft, HS


    A novel solid-phase synthesis strategy toward succinylhydroxamate peptides, using an appropriately protected hydroxamate building block, is described. Rapid and efficient access is gained to amine-functionalized peptides, which can be decorated with, for instance, a fluorescent label. In addition, w

  9. A convenient procedure for the solid-phase synthesis of hydroxamic acids on PEGA resins

    Nandurkar, Nitin Subhash; Petersen, Rico; Qvortrup, Katrine


    An efficient method for the solid-phase synthesis of hydroxamic acids is described. The method comprises the nucleophilic displacement of esters immobilized on PEGA resins with hydroxylamine/sodium hydroxide in isopropanol. The hydroxyaminolysis protocol is compatible with a broad range of PEGA-s...

  10. Linkers, resins, and general procedures for solid-phase peptide synthesis

    Shelton, Anne Pernille Tofteng; Jensen, Knud Jørgen


    and linkers for solid-phase synthesis is a key parameter for successful peptide synthesis. This chapter provides an overview of the most common and useful resins and linkers for the synthesis of peptides with C-terminal amides, carboxylic acids, and more. The chapter finishes with robust protocols for general...

  11. Total synthesis of human urotension-Ⅱ by microwave-assisted solid phase method


    Human urotension-Ⅱ was synthesized efficiently on Wang resin under microwave irradiation using Fmoc/tBu orthogonal protection strategy. Disulphide bridge was formed on solid phase with the irradiation of microwave, then the whole peptide was cleaved from the resin. The purity of crude peptide cyclized under microwave irradiation was higher than that under room temperature.

  12. Electrocatalytic phenomena in gas phase reactions in solid electrolyte electrochemical cells

    Gellings, P.J.; Koopmans, H.J.A.; Burggraaf, A.J.


    The recent literature on electrocatalysis and electrocatalytic phenomena occurring in gas phase reactions on solid, oxygen conducting electrolytes is reviewed. In this field there are a number of different subjects which are treated separately. These are: the use of electrochemical methods to study

  13. Solid-phase Synthesis of a Novel Kind of Hydroxylated Heterocyclic Ketene Aminals

    Tao PENG; Chu Yi YU; Zhi Tang HUANG


    An efficient solid-phase synthesis method for novel heterocyclic ketene aminals containing a hydroxyl group has been developed. The loading of the substrate on the resin through the hydroxyl group and the protection of the amine by the Schiff base were the key steps in the synthesis.

  14. Fibers coated with molecularly imprinted polymers for solid-phase microextraction

    Koster, E.H M; Crescenzi, C; den Hoedt, W; Ensing, K; de Jong, G.J.


    The simplicity and flexibility of solid-phase microextraction have been combined with the selectivity of molecularly imprinted polymers (MIPs), Silica fibers were coated reproducible with a 75-mum layer of methacrylate polymer either nonimprinted or imprinted with clenbuterol to compare their extrac

  15. Dynamic speciation analysis of atrazine in aqueous latex nanoparticle dispersions using solid phase microextraction (SPME)

    Benhabib, K.; Town, R.M.; Leeuwen, van H.P.


    Solid phase microextraction (SPME) is applied in the dynamic speciation analysis of the pesticide atrazine in an aqueous medium containing sorbing latex nanoparticles. It is found that the overall rate of extraction of the analyte is faster than in the absence of nanoparticles and governed by the

  16. Investigating the Retention Mechanisms of Liquid Chromatography Using Solid-Phase Extraction Cartridges

    O'Donnell, Mary E.; Musial, Beata A.; Bretz, Stacey Lowery; Danielson, Neil D.; Ca, Diep


    Liquid chromatography (LC) experiments for the undergraduate analytical laboratory course often illustrate the application of reversed-phase LC to solve a separation problem, but rarely compare LC retention mechanisms. In addition, a high-performance liquid chromatography instrument may be beyond what some small colleges can purchase. Solid-phase…

  17. Solid-Phase Synthesis of Smac Peptidomimetics Incorporating Triazoloprolines and Biarylalanines

    Le Quement, Sebastian T.; Ishoey, Mette; Petersen, Mette T.;


    -Me)AVPF sequence, peptides incorporating triazoloprolines and biarylalanines were synthesized by means of Cu(I)-catalyzed azide–alkyne cycloaddition and Pd-catalyzed Suzuki cross-coupling reactions. Solid-phase procedures were optimized to high efficiency, thus accessing all products in excellent crude purities...

  18. Highly Selective Liquid-Phase Benzylation of Anisole with Solid-Acid Zeolite Catalysts

    Poreddy, Raju; Shunmugavel, Saravanamurugan; Riisager, Anders


    Zeolites were evaluated as solid acid catalysts for the liquid-phase benzylation of anisole with benzyl alcohol, benzyl bromide, and benzyl chloride at 80 °C. Among the examined zeolites, H-mordenite-10 (H-MOR-10) demonstrated particular high activity (>99 %) and excellent selectivity (>96...

  19. Rapid and convenient semi-automated microwave-assisted solid-phase synthesis of arylopeptoids

    Rasmussen, Jakob Ewald; Boccia, Marcello Massimo; Nielsen, John


    A facile and expedient route to the synthesis of arylopeptoid oligomers (N-alkylated aminomethyl benz-amides) using semi-automated microwave-assisted solid-phase synthesis is presented. The synthesis was optimized for the incorporation of side chains derived from sterically hindered or unreactive...

  20. Combined supercritical fluid extraction/solid-phase extraction with octadecylsilane cartridges as a sample preparation technique for the ultratrace analysis of a drug metabolite in plasma.

    Liu, H; Cooper, L M; Raynie, D E; Pinkston, J D; Wehmeyer, K R


    Supercritical fluid extraction was coupled with solid-phase extraction using octadecylsilane cartridges for the selective isolation of ultratrace levels of a drug metabolite, mebeverine alcohol, from plasma. Plasma was directly applied to the extraction cartridge, the cartridge was washed to remove protein and then extracted under supercritical conditions using CO2/5% methanol. The effluent from the extraction cell was bubbled through a small volume of 2-propanol to trap the extracted mebeverine alcohol. The effects of extraction pressure and temperature on analyte recovery were examined. The absolute recovery, selectivity, precision, and accuracy of the combined supercritical fluid extraction/solid-phase extraction approach were compared to those of conventional solid-phase extraction using gas chromatography/mass spectrometry in the selected-ion monitoring mode. Mebeverine alcohol was used as a model compound, and dog plasma was employed as the biological matrix for these studies.

  1. Direct visualization of solid ordered domains induced by polyene antibiotics in giant unilamellar vesicles.

    Chulkov, Evgeny G; Efimova, Svetlana S; Schagina, Ludmila V; Ostroumova, Olga S


    Polyene antibiotics isolated from Streptomyces are frequently used in treatment of mycoses. Confocal fluorescence microscopy has been employed to investigate the influence of polyene macrolide antibiotics nystatin, amphotericin B, and filipin on the phase separation in giant unilamellar vesicles. It has been demonstrated that nystatin produced the solid ordered domains in vesicles made from DOPC/Chol, DOPC/Chol/SM, and POPC while DOPC vesicles remained homogenous in the presence of polyene antibiotics. The ability of various polyenes to produce the solid ordered phase in POPC membranes has been compared. It has been shown that amphotericin B produced phase separation at lower concentration as compared with nystatin and filipin. Filipin was less effective in promotion of gel domains. The observed efficiency of polyene antibiotics to induce phase separation in lipid bilayers correlates with their biological activity. Present findings probably indicate the limitations of using of polyenes as fluorescence membrane probes for determination of strerol-enriched domains in plasma membrane of live cells.

  2. Solid Phase Microextraction and Related Techniques for Drugs in Biological Samples

    Mohammad Mahdi Moein


    Full Text Available In drug discovery and development, the quantification of drugs in biological samples is an important task for the determination of the physiological performance of the investigated drugs. After sampling, the next step in the analytical process is sample preparation. Because of the low concentration levels of drug in plasma and the variety of the metabolites, the selected extraction technique should be virtually exhaustive. Recent developments of sample handling techniques are directed, from one side, toward automatization and online coupling of sample preparation units. The primary objective of this review is to present the recent developments in microextraction sample preparation methods for analysis of drugs in biological fluids. Microextraction techniques allow for less consumption of solvent, reagents, and packing materials, and small sample volumes can be used. In this review the use of solid phase microextraction (SPME, microextraction in packed sorbent (MEPS, and stir-bar sorbtive extraction (SBSE in drug analysis will be discussed. In addition, the use of new sorbents such as monoliths and molecularly imprinted polymers will be presented.

  3. Chromium speciation in environmental samples using a solid phase spectrophotometric method

    Amin, Alaa S.; Kassem, Mohammed A.


    A solid phase extraction technique is proposed for preconcentration and speciation of chromium in natural waters using spectrophotometric analysis. The procedure is based on sorption of chromium(III) as 4-(2-benzothiazolylazo)2,2'-biphenyldiol complex on dextran-type anion-exchange gel (Sephadex DEAE A-25). After reduction of Cr(VI) by 0.5 ml of 96% concentrated H2SO4 and ethanol, the system was applied to the total chromium. The concentration of Cr(VI) was calculated as the difference between the total Cr and the Cr(III) content. The influences of some analytical parameters such as: pH of the aqueous solution, amounts of 4-(2-benzothiazolylazo)2,2'-biphenyldiol (BTABD), and sample volumes were investigated. The absorbance of the gel, at 628 and 750 nm, packed in a 1.0 mm cell, is measured directly. The molar absorptivities were found to be 2.11 × 107 and 3.90 × 107 L mol-1 cm-1 for 500 and 1000 ml, respectively. Calibration is linear over the range 0.05-1.45 μg L-1 with RSD of waters and total chromium preconcentration in microwave digested tobacco, coffee, tea, and soil samples. The results were simultaneously compared with those obtained using an ET AAS method, whereby the validity of the method has been tested.

  4. Altering the interfacial activation mechanism of a lipase by solid-phase selective chemical modification.

    López-Gallego, Fernando; Abian, Olga; Guisán, Jose Manuel


    This study presents a combined protein immobilization, directed mutagenesis, and site-selective chemical modification approach, which was used to create a hyperactivated semisynthetic variant of BTL2. Various alkane chains were tethered at three different positions in order to mimic the lipase interfacial activation exogenously triggered by detergents. Optimum results were obtained when a dodecane chain was introduced at position 320 by solid-phase site-selective chemical modification. The resulting semisynthetic variant showed a 2.5-fold higher activity than the wild-type nonmodified variant in aqueous conditions. Remarkably, this is the maximum hyperactivation ever observed for BTL2 in the presence of detergents such as Triton X-100. We present evidence to suggest that the endogenous dodecane chain hyperactivates the enzyme in a similar fashion as an exogenous detergent molecule. In this way, we also observe a faster irreversible enzyme inhibition and an altered detergent sensitivity profile promoted by the site-selective chemical modification. These findings are also supported by fluorescence studies, which reveal that the structural conformation changes of the semisynthetic variant are different to those of the wild type, an effect that is more pronounced in the presence of detergent. Finally, the optimal immobilized semisynthetic variant was successfully applied to the selective synthesis of oxiran-2-yl butyrate. Significantly, this biocatalyst is 12-fold more efficient than the immobilized wild-type enzyme, producing the S-enantiomer with higher enantiospecificity (ee = 92%).

  5. Determination of volatile organic compounds in river water by solid phase extraction and gas chromatography

    M. A. Mottaleb; M. Z. Abedin; M. S. Islam


    A simple, rapid, and reproducible method is described employing solid-phase extraction(SPE) using dichloromethane followed by gas chromatography(GC) with flame ionization detection(FID) for determination of volatile organic compound(VOC) from the Buriganga River water of Bangladesh. The method was applied to detect the benzene, toluene, ethylbenzene, xylene and cumene(BTEXC) in the sample collected from the surface or 15 cm depth of water. Two-hundred ml of n-hexane-pretreated and filtered water samples were applied directly to a C18 SPE column. BTEXC were extracted with dichloromethane and average concentrations were obtained as 0.104 to 0.372 (g/ml. The highest concentration of benzene was found as 0.372 (g/ml with a relative standard deviation(RSD) of 6.2%, and cumene was not detected. Factors influencing SPE e.g., adsorbent types, sample load volume, eluting solvent, headspace and temperatures, were investigated. A cartridge containing a C18 adsorbent and using dichloromethane gave better performance for extraction of BTEXC from water.Average recoveries exceeding 90% could be achieved for cumene at 4℃with a 2.7%RSD

  6. Graphenized pencil lead fiber: facile preparation and application in solid-phase microextraction.

    Liu, Qian; Cheng, Mengting; Long, Yanmin; Yu, Miao; Wang, Thanh; Jiang, Guibin


    Graphenized pencil lead fiber was facilely prepared by in situ chemical exfoliation of graphite in pencil lead fiber to few-layered graphene sheets via a one-pot, one-step pressurized oxidation reaction for the first time. This new fiber was characterized and demonstrated to be a highly efficient but low-cost solid-phase microextraction (SPME) fiber. The extraction performance of the fiber was evaluated with four bisphenol analogs [bisphenol A (BPA), bisphenol S (BPS), bisphenol AF (BPAF), and tetrabromobisphenol A (TBBPA)] as model analytes in direct SPME mode. Unlike commercially available fibers, the graphenized pencil lead fiber showed an excellent chemical stability in highly saline, acidic, alkaline and organic conditions due to its coating-free configuration. The fiber also showed a very long lifespan. Furthermore, high extraction efficiency and good selectivity for the analytes with a wide polarity range could be obtained due to the exceptional properties of graphene. The detection limits (LODs) for the analytes were in the range of 1.1-25ng/L. The fiber was successfully applied in the analysis of tap water and effluent samples from a waste water treatment plant with spike recoveries ranging from 68.5 to 105.1%. Therefore, the graphenized pencil lead fiber provides a high performance, cheap, robust, and reliable tool for SPME.

  7. Determination of organic acids in Salicornia herbacea by solid-phase extraction combined with liquid chromatography.

    Han, Dandan; Tian, Minglei; Park, Dong Wha; Row, Kyung Ho


    A solid-phase extraction (SPE) method for the determination of procatechuic acid, ferulic acid and caffeic acid in Salicornia herbacea L. (Hamcho) has been developed. The optimal conditions were obtained by using a C18 SPE cartridge. By using ethanol and acetonitrile /water/ trifluoracetic acid as washing and eluting solvents, most interfering compounds originating from the hamcho matrix were eliminated. The extracts were sufficiently clean to be directly injected into the HPLC for further chromatographic analysis. Good linearity was obtained from 0.1 to 200 microg/mL (r > 0.999) for procatechuic acid, 0.2 to 400 microg/mL (r > 0.999) for caffeic acid and 0.3 to 600 microg/mL (r > 0.999) for ferulic acid, with the relative standard deviations being less than 3.6%. The mean recoveries of procatechuic acid, ferulic acid and caffeic acid from hamcho were more than 79.2% and the detection limit (S/N = 3:1) was 0.02 microg/mL for procatechuic acid, 0.01 microg/mL for caffeic acid and 0.04 microg/mL for ferulic acid. This method is a viable alternative to the existing HPLC methods for analyzing the content of procatechuic acid, ferulic acid and caffeic acid in hamcho.

  8. Robust aptamer sol-gel solid phase microextraction of very polar adenosine from human plasma.

    Mu, Li; Hu, Xiangang; Wen, Jianping; Zhou, Qixing


    Conventional solid phase microextraction (SPME) has a limited capacity to extract very polar analytes, such as adenosine. To solve this problem, aptamer conjugating sol-gel methodology was coupled with an SPME fiber. According to the authors' knowledge, this is the first reported use of aptamer SPME. The fiber of aptamer sol-gel SPME with a mesoporous structure has high porosity, large surface area, and small water contact angle. Rather than employing direct entrapment, covalent immobilization was the dominant method of aptamer loading in sol-gel. Aptamer sol-gel fiber captured a specified analyte from among the analog molecules, thereby, exhibiting an excellent selective property. Compared with commercial SPME fibers, this aptamer fiber was suitable for extracting adenosine, presenting an extraction efficiency higher than 20-fold. The values of repeatability and reproducibility expressed by relative standard deviation were low (9.4%). Interestingly, the sol-gel network enhanced the resistance of aptamer SPME to both nuclease and nonspecific proteins. Furthermore, the aptamer sol-gel fiber was applied in human plasma with LOQ 1.5 μg/L, which is an acceptable level. This fiber also demonstrates durability and regeneration over 20-cycles without significant loss of efficiency. Given the various targets (from metal ions to biomacromolecules and cells) of aptamers, this methodology will extend the multi-domain applications of SPME.

  9. Determination of Three Tanshinones from Radix Salvia Miltiorrhiza by Molecularly Imprinted Solid-phase Extraction

    YAN, Hongyuan; TIAN, Minglei; ROW, Kyung Ho


    A selective molecularly imprinted solid-phase extraction procedure was developed for the selective separation of tanshinone Ⅰ, tanshinone ⅡA, and cryptotanshinone from Radix Salvia Miltiorrhiza samples. Tanshinone ⅡA imprinted polymers (MIP) synthesized in ethanol-dodecanol system show high affinity to tanshinone ⅡA and its structure analogs in aqueous environment and the affinity can be controlled by adjusting the intensity of the eluents. By using 60% water-40% methanol (volume ratio) and 99.5% methanol-0.5% trifluoroacetic acid (volume ratio) as washing and eluting solvents, most interferences originating from the salvia matrix were eliminated. The extracts were sufficiently clean enough to be directly injected into HPLC for further chromatographic analysis. Good linearity was obtained from 0.4 to 500.0 mg·L~(-1) (r~2=0.999) with the relative standard deviations less than 4.2%. The mean recoveries of tanshinone ⅡA in Radix Salvia Miltiorrhiza were more than 85.6% at three different concentrations and the limits of detection were 0.06-0.09 mg·L~(-1). This method is a viable alternative tool to the existing HPLC methods for analyzing the content of the three tanshinones in Radix Salvia Miltiorrhiza samples.

  10. Continuum simulation of solid phase epitaxial regrowth of amorphized silicon including most advanced physical interactions

    Delalleau, Julien; Simola, Roberto [STMicroelectronics, ZI de Rousset, BP 2, 13106 Rousset (France); Pakfar, Ardechir; Tavernier, Clement [STMicroelectronics, 850 rue Jean Monnet, 38926 Crolles Cedex (France); Bazizi, El-Medhi [STMicroelectronics, 850 rue Jean Monnet, 38926 Crolles Cedex (France); LAAS/CNRS, University of Toulouse, 7 av. Col. Roche, 31077 Toulouse (France); CEMES/CNRS, 29 rue J. Marvig, 31055 Toulouse (France)


    Solid-phase-epitaxial regrowth (SPER) of Si amorphized by ion implantation is considered as a potential solution for the fabrication of highly-activated ultra-shallow junctions for future technology nodes of Si CMOS devices. In the frame of 32 and 22 nm technologies node development, SPER occurs after amorphizing implantations used in source/drain regions. To get an accurate simulation of dopant activation and junction depth position, a suitable continuum SPER model, implemented into a commercial simulator, is now mandatory. This TCAD model must consider the different physical effects associated with SPER: silicon regrowth rate, dopants redistribution snow plough effect, and interaction with silicon point defects. In this work, using a previously established model, we have implemented an improved physically based model for SPER and, several formulations have been developed to enable a robust/accurate modeling of the recrystallization velocity. It takes into account the direct interaction between amorphous/crystalline interface kinetics and point defects, and a regrowth rate dependent on temperature. Simulation results of dopant concentration profiles are in good agreement with experimental data and can provide important insight for optimizing the bulk silicon process as well in one dimension as two dimensions. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. Determination of formaldehyde in Brazilian alcohol fuels by flow-injection solid phase spectrophotometry

    Teixeira, Leonardo S.G.; Leao, Elsimar S.; Dantas, Alailson F.; Pinheiro, Heloisa L.C.; Costa, Antonio C.S.; De Andrade, Jailson B. [Instituto de Quimica-Universidade Federal da Bahia, Campus Universitario de Ondina, 40.170-280-Salvador, Bahia (Brazil)


    In this work, a solid phase spectrophotometric method in association with flow injection analysis for formaldehyde determination has been developed with direct measurement of light-absorption in C{sub 18} material. The 3,5-diacetyl-1,4-dihydrolutidine produced from the reaction between formaldehyde and fluoral P was quantitatively retained on C{sub 18} support and the spectrophotometric detection was performed simultaneously at 412nm. The retained complex was quickly eluted from C{sub 18} material with the eluent stream consisting of a 50% (v/v) ethanol solution. The results showed that the proposed method is simple, rapid and the analytical response is linear in the concentration range of 0.050-1.5mgL{sup -1}. The limit of detection was estimated as 30{mu}mgL{sup -1} and the R.S.D. 2.2% using a sample volume of 625{mu}mL. The system presented an analytical throughput of 20 determinations per hour. The method was successfully applied in the determination of formaldehyde in ethanol fuel.

  12. Determination of formaldehyde in Brazilian alcohol fuels by flow-injection solid phase spectrophotometry.

    Teixeira, Leonardo S G; Leão, Elsimar S; Dantas, Alaílson F; Pinheiro, Heloísa L C; Costa, Antonio C S; de Andrade, Jailson B


    In this work, a solid phase spectrophotometric method in association with flow injection analysis for formaldehyde determination has been developed with direct measurement of light-absorption in C(18) material. The 3,5-diacetyl-1,4-dihydrolutidine produced from the reaction between formaldehyde and fluoral P was quantitatively retained on C(18) support and the spectrophotometric detection was performed simultaneously at 412nm. The retained complex was quickly eluted from C(18) material with the eluent stream consisting of a 50% (v/v) ethanol solution. The results showed that the proposed method is simple, rapid and the analytical response is linear in the concentration range of 0.050-1.5mgL(-1). The limit of detection was estimated as 30mugL(-1) and the R.S.D. 2.2% using a sample volume of 625muL. The system presented an analytical throughput of 20 determinations per hour. The method was successfully applied in the determination of formaldehyde in ethanol fuel.

  13. Determination of aflatoxins in rice samples by ultrasound-assisted matrix solid-phase dispersion.

    Manoochehri, Mahboobeh; Asgharinezhad, Ali Akbar; Safaei, Mahdi


    This work describes the application of ultrasound-assisted matrix solid-phase dispersion as an extraction and sample preparation approach for aflatoxins (B1, B2, G1 and G2) and subsequent determination of them by high-performance liquid chromatography-fluorescence detection. A Box-Behnken design in combination with response surface methodology was used to determine the affecting parameters on the extraction procedure. The influence of different variables including type of dispersing phase, sample-to-dispersing phase ratio, type and quantity of clean-up phase, ultrasonication time, ultrasonication temperature, nature and volume of the elution solvent was investigated in the optimization study. C18, primary-secondary amine (PSA) and acetonitrile were selected as dispersing phase, clean-up phase and elution solvent, respectively. The obtained optimized values were sample-to-dispersing phase ratio of 1 : 1, 60 mg of PSA, 11 min ultrasonication time, 30°C ultrasonication temperature and 4 mL acetonitrile. Under the optimal conditions, the limits of detection were ranged from 0.09 to 0.14 ng g(-1) and the precisions [relative standard deviation (RSD%)] were <8.6%. The recoveries of the matrix solid-phase dispersion process ranged from 78 to 83% with RSD <10% in all cases. Finally, this method was successfully applied to the extraction of trace amounts of aflatoxins in rice samples. © The Author [2014]. Published by Oxford University Press. All rights reserved. For Permissions, please email:

  14. Break-down of a planar liquid-solid interface during directional solidification - Influence of convection

    Tewari, S. N.; Chopra, M. A.


    The influence of convection on the development of morphological instability at the liquid-solid interface during directional solidification in a positive thermal gradient has been examined in Pb-10 wt pct Sn and succinonitrile-1.9 wt pct acetone. The onset of interfacial breakdown occurs at higher growth speeds in the presence of convection. The linear stability analysis due to Favier and Rouzaud which uses the 'deformable' mass flow boundary layer concept shows a good agreement with the experimentally observed behavior.

  15. A magnetic field-directed self-assembly solid contact for construction of an all-solid-state polymeric membrane Ca(2+)-selective electrode.

    Yin, Tanji; Jiang, Xiaojing; Qin, Wei


    A magnetic field-directed self-assembly solid contact has been proposed for developing an all-solid-state polymeric membrane Ca(2+)-selective electrode. The solid contact is prepared by physically adsorbing magnetic graphene powder on a magnetic gold electrode under the direction of the magnetic field. The proposed method for preparing solid contact avoids using the aqueous solutions and is simple, fast and general as compared to the multilayer drop-casting and electrodeposition methods. The all-solid-state Ca(2+)-selective electrode based on magnetic graphene as solid contact shows a stable potential response in the linear range of 1.0 × 10(-6)-1.0 × 10(-3) M with a slope of 28.2 mV/decade, and the detection limit is about 4.0 × 10(-7) M. Additionally, the magnetic graphene-based electrode shows a comparable potential stability performance to other graphene-based all-solid-state ion-selective electrodes, such as reduced undesirable water layer and insensitive to the interferences of O2, CO2 and light. This work provides a favorable way to prepare solid contact for use in the field of all-solid-state ion-selective electrodes. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Mass spectrometric methods for the direct elemental and isotopic analysis of solid material

    Ganeev, A. A.; Gubal, A. R.; Potapov, S. V.; Agafonova, N. N.; Nemets, V. M.


    Methods for the direct analysis of solids have a number of undeniable advantages over the methods that require preliminary dissolution of samples. High sensitivity and selectivity make the direct mass spectrometric techniques the most in-demand. The review concerns spark source mass spectrometry, laser ionization mass spectrometry, laser ablation inductively coupled plasma mass spectrometry, secondary ion mass spectrometry, secondary neutral mass spectrometry and glow discharge mass spectrometry. Basic principles, analytical characteristics and trends in the development of these techniques are discussed. Particular attention is given to applications of the techniques as well as to their competitive advantages and drawbacks. The bibliography includes 123 references.

  17. Fluorine determination in coal using high-resolution graphite furnace molecular absorption spectrometry and direct solid sample analysis

    Machado, Patrícia M.; Morés, Silvane; Pereira, Éderson R. [Departamento de Química, Universidade Federal de Santa Catarina, 88040-900 Florianópolis, SC (Brazil); Welz, Bernhard, E-mail: [Departamento de Química, Universidade Federal de Santa Catarina, 88040-900 Florianópolis, SC (Brazil); Instituto Nacional de Ciência e Tecnologia do CNPq, INCT de Energia e Ambiente, Universidade Federal da Bahia, 40170-115 Salvador, BA (Brazil); Carasek, Eduardo [Departamento de Química, Universidade Federal de Santa Catarina, 88040-900 Florianópolis, SC (Brazil); Andrade, Jailson B. de [Instituto Nacional de Ciência e Tecnologia do CNPq, INCT de Energia e Ambiente, Universidade Federal da Bahia, 40170-115 Salvador, BA (Brazil)


    The absorption of the calcium mono-fluoride (CaF) molecule has been employed in this study for the determination of fluorine in coal using direct solid sample analysis and high-resolution continuum source graphite furnace molecular absorption spectrometry (HR-CS GF MAS). The rotational line at 606.440 nm was used for measuring the molecular absorption in the gas phase. The pyrolysis and vaporization temperatures were 700 °C and 2100 °C, respectively. Different chemical modifiers have been studied, such as Pd and Ir as permanent modifiers, and Pd and the mixed Pd/Mg modifier in solution. The limit of detection and the characteristic mass were 0.3 and 0.1 ng F, respectively. One certified reference material (CRM) of coal (NIST 1635) and four CRMs with a non-certified value for F (SARM 18, SARM 20, BCR 40, BCR 180) were used to evaluate the accuracy and precision of the method, obtaining good agreement (104%) with the certified value and with the informed values (ranging from 90 to 103%). - Highlights: • High-resolution Graphite Furnace Molecular Absorption Spectrometry (HR-GF MAS) • Fluorine has been determined using HR-GF MAS of the CaF molecule. • The CaF molecule was generated in a graphite furnace at a temperature of 2100 °C • Coal samples have been analyzed using direct solid sample introduction. • Aqueous standard solutions have been used for calibration.



    In this paper, an energy equation of silt-laden water flow is educed based on the energy equation of continuum fluid flow. The dissipation functions of liquid phase and solid phase are presented respectively. Then the extremity law of energy dissipation rate is introduced for the research of the silt-laden water flow and a new mathematical model is developed. The corresponding procedure based on the finite difference method (FDM) is developed to calculate the two phase flow in hydraulic turbine. The method is applied to analyze the silt-laden water flow between stay vanes, and the numerical results are in good agreement with the experimental ones.

  19. Phase separation kinetics in amorphous solid dispersions upon exposure to water.

    Purohit, Hitesh S; Taylor, Lynne S


    The purpose of this study was to develop a novel fluorescence technique employing environment-sensitive fluorescent probes to study phase separation kinetics in hydrated matrices of amorphous solid dispersions (ASDs) following storage at high humidity and during dissolution. The initial miscibility of the ASDs was confirmed using infrared (IR) spectroscopy and differential scanning calorimetry (DSC). Fluorescence spectroscopy, as an independent primary technique, was used together with conventional confirmatory techniques including DSC, X-ray diffraction (XRD), fluorescence microscopy, and IR spectroscopy to study phase separation phenomena. By monitoring the emission characteristics of the environment-sensitive fluorescent probes, it was possible to successfully monitor amorphous-amorphous phase separation (AAPS) as a function of time in probucol-poly(vinylpyrrolidone) (PVP) and ritonavir-PVP ASDs after exposure to water. In contrast, a ritonavir-hydroxypropylmethylcellulose acetate succinate (HPMCAS) ASD, did not show AAPS and was used as a control to demonstrate the capability of the newly developed fluorescence method to differentiate systems that showed no phase separation following exposure to water versus those that did. The results from the fluorescence studies were in good agreement with results obtained using various other complementary techniques. Thus, fluorescence spectroscopy can be utilized as a fast and efficient tool to detect and monitor the kinetics of phase transformations in amorphous solid dispersions during hydration and will help provide mechanistic insight into the stability and dissolution behavior of amorphous solid dispersions.

  20. Cluster-based composition rule for Laves phase-related BCC solid solution hydrogen storage alloys

    WANG Qing; CHEN Feng; WU Jiang; QIANG Jianbing; DONG Chuang; ZHANG Yao; XU Fen; SUN Lixian


    A new cluster line approach for the composition rule of Laves phase-related BCC solid solution hydrogen-storage alloys was presented. The cluster line in a ternary phase diagram refers to a straight composition line linking a specific binary cluster to the third element. In the Laves phase-related BCC solid solution alloy system such as Ti-Cr-V, Ti-Cr tends to form binary Cr2Ti Laves phase while Ti-V and Cr-V to form solid solutions. This Laves phase is characterized by a close-packing icosahedral cluster Cr7Ti6. A cluster line Cr7Ti6-V is then constructed in this system. Alloy rods with a diameter of 3 mm of compositions along this line were prepared by copper-mould suction method. The alloy structure is found to vary with the V contents. Furthermore, the P-C-T measurements indicate that the cluster-line (Cr7Ti6)1-xVx alloys have large hydrogen storage capacities.

  1. Accelerated exploration of multi-principal element alloys with solid solution phases

    Senkov, O. N.; Miller, J. D.; Miracle, D. B.; Woodward, C.


    Recent multi-principal element, high entropy alloy (HEA) development strategies vastly expand the number of candidate alloy systems, but also pose a new challenge—how to rapidly screen thousands of candidate alloy systems for targeted properties. Here we develop a new approach to rapidly assess structural metals by combining calculated phase diagrams with simple rules based on the phases present, their transformation temperatures and useful microstructures. We evaluate over 130,000 alloy systems, identifying promising compositions for more time-intensive experimental studies. We find the surprising result that solid solution alloys become less likely as the number of alloy elements increases. This contradicts the major premise of HEAs—that increased configurational entropy increases the stability of disordered solid solution phases. As the number of elements increases, the configurational entropy rises slowly while the probability of at least one pair of elements favouring formation of intermetallic compounds increases more rapidly, explaining this apparent contradiction.

  2. Accelerated exploration of multi-principal element alloys with solid solution phases.

    Senkov, O N; Miller, J D; Miracle, D B; Woodward, C


    Recent multi-principal element, high entropy alloy (HEA) development strategies vastly expand the number of candidate alloy systems, but also pose a new challenge--how to rapidly screen thousands of candidate alloy systems for targeted properties. Here we develop a new approach to rapidly assess structural metals by combining calculated phase diagrams with simple rules based on the phases present, their transformation temperatures and useful microstructures. We evaluate over 130,000 alloy systems, identifying promising compositions for more time-intensive experimental studies. We find the surprising result that solid solution alloys become less likely as the number of alloy elements increases. This contradicts the major premise of HEAs--that increased configurational entropy increases the stability of disordered solid solution phases. As the number of elements increases, the configurational entropy rises slowly while the probability of at least one pair of elements favouring formation of intermetallic compounds increases more rapidly, explaining this apparent contradiction.

  3. Profilometry of discontinuous solids by means of co-phased demodulation of projected fringes with RGB encoding

    Padilla, J. M.; Servin, M.; Garnica, G.


    Here we describe a 2-projectors and 1-camera setup for profilometry of discontinuous solids by means of co-phased demodulation of projected fringes and red, green, and blue (RGB) multichannel operation. The dual projection configuration for this profilometer is proposed to solve efficiently specular regions and self-occluding shadows due to discontinuities, which are the main drawbacks for a 1-projector 1-camera configuration. This is because the regions where shadows and specular reflections are generated, and the fringe contrast drops to zero, are in general different for each projection direction; thus, the resulting fringe patterns will have complementary phase information. Multichannel RGB operation allows us to work simultaneously with both projectors and to record independently the complementary fringe patterns phase-modulated by the 3D profile of the object under study. In other words, color encoding/decoding reduces the acquisition time respect to one-at-a-time grayscale operation and, in principle, enables the study of dynamic phenomena. The co-phased demodulation method implemented in this work benefits from the complex (analytic) nature of the output signals estimated with most phase demodulation methods (such as the Fourier method, and temporal phaseshifting algorithms). This allowed us to straightforwardly generate a single phase-map well-defined for the entire area of interest. Finally we assessed our proposed profilometry setup by measuring a fractured spherical cap made of (uncoated) expanded polystyrene. The results were satisfactory but in the authors' opinion this must be considered a preliminary report.

  4. A phase-field approach to nonequilibrium phase transformations in elastic solids via an intermediate phase (melt) allowing for interface stresses.

    Momeni, Kasra; Levitas, Valery I


    A phase-field approach for phase transformations (PTs) between three different phases at nonequilibrium temperatures is developed. It includes advanced mechanics, thermodynamically consistent interfacial stresses, and interface interactions. A thermodynamic Landau-Ginzburg potential developed in terms of polar order parameters satisfies the desired instability and equilibrium conditions for homogeneous phases. The interfacial stresses were introduced with some terms from large-strain formulation even though the small-strain assumption was utilized. The developed model is applied to study the PTs between two solid phases via a highly disordered intermediate phase (IP) or an intermediate melt (IM) hundreds of degrees below the melting temperature. In particular, the β ↔ δ PTs in HMX energetic crystals via IM are analyzed. The effects of various parameters (temperature, ratios of widths and energies of solid-solid (SS) to solid-melt (SM) interfaces, elastic energy, and interfacial stresses) on the formation, stability, and structure of the IM within a propagating SS interface are studied. Interfacial and elastic stresses within a SS interphase and their relaxation and redistribution with the appearance of a partial or complete IM are analyzed. The energy and structure of the critical nucleus (CN) of the IM are studied as well. In particular, the interfacial stresses increase the aspect-ratio of the CN. Although including elastic energy can drastically reduce the energy of the CN of the IM, the activation energy of the CN of the IM within the SS interface increases when interfacial tension is taken into account. The developed thermodynamic potential can also be modified to model other multiphase physical phenomena, such as multi-variant martensitic PTs, grain boundary and surface-induced pre-melting and PTs, as well as developing phase diagrams for IPs.

  5. A Variational Model for Two-Phase Immiscible Electroosmotic Flow at Solid Surfaces

    Shao, Sihong


    We develop a continuum hydrodynamic model for two-phase immiscible flows that involve electroosmotic effect in an electrolyte and moving contact line at solid surfaces. The model is derived through a variational approach based on the Onsager principle of minimum energy dissipation. This approach was first presented in the derivation of a continuum hydrodynamic model for moving contact line in neutral two-phase immiscible flows (Qian, Wang, and Sheng, J. Fluid Mech. 564, 333-360 (2006)). Physically, the electroosmotic effect can be formulated by the Onsager principle as well in the linear response regime. Therefore, the same variational approach is applied here to the derivation of the continuum hydrodynamic model for charged two-phase immiscible flows where one fluid component is an electrolyte exhibiting electroosmotic effect on a charged surface. A phase field is employed to model the diffuse interface between two immiscible fluid components, one being the electrolyte and the other a nonconductive fluid, both allowed to slip at solid surfaces. Our model consists of the incompressible Navier-Stokes equation for momentum transport, the Nernst-Planck equation for ion transport, the Cahn-Hilliard phase-field equation for interface motion, and the Poisson equation for electric potential, along with all the necessary boundary conditions. In particular, all the dynamic boundary conditions at solid surfaces, including the generalized Navier boundary condition for slip, are derived together with the equations of motion in the bulk region. Numerical examples in two-dimensional space, which involve overlapped electric double layer fields, have been presented to demonstrate the validity and applicability of the model, and a few salient features of the two-phase immiscible electroosmotic flows at solid surface. The wall slip in the vicinity of moving contact line and the Smoluchowski slip in the electric double layer are both investigated. © 2012 Global-Science Press.

  6. Optical manipulation of the Berry phase in a solid-state spin qubit

    Yale, Christopher G.; Heremans, F. Joseph; Zhou, Brian B.; Auer, Adrian; Burkard, Guido; Awschalom, David D.


    Phase relations between quantum states represent a resource for storing and processing quantum information. Although quantum phases are commonly controlled dynamically by tuning energetic interactions, the use of geometric phases that accumulate during cyclic evolution may offer superior robustness to noise. To date, demonstrations of geometric phase in solid-state systems employ microwave fields that have limited spatial resolution. Here, we demonstrate an all-optical method to accumulate a geometric phase, the Berry phase, in an individual nitrogen-vacancy centre in diamond. Using stimulated Raman adiabatic passage controlled by diffraction-limited laser light, we loop the nitrogen-vacancy centre's spin around the Bloch sphere to enclose an arbitrary Berry phase. We investigate the limits of this control due to the loss of adiabaticity and decoherence, as well as its robustness to noise introduced into the experimental control parameters. These techniques set the foundation for optical geometric manipulation in photonic networks of solid-state qubits linked and controlled by light.

  7. A lab-on-a-chip device for rapid identification of avian influenza viral RNA by solid-phase PCR

    Yi, Sun; Dhumpa, Raghuram; Bang, Dang Duong


    This paper describes a lab-on-a-chip device for fast AIV screening by integrating DNA microarray-based solid-phase PCR on a microfluidic chip.......This paper describes a lab-on-a-chip device for fast AIV screening by integrating DNA microarray-based solid-phase PCR on a microfluidic chip....

  8. A photolabile linker for the solid-phase synthesis of 4-substituted NH-1,2,3-triazoles

    Qvortrup, Katrine; Nielsen, Thomas Eiland


    A novel photolabile linker for solid-phase synthesis is presented. The linker displays an azido handle for copper-catalyzed azide–alkyne cycloaddition reactions with a variety of alkynes, remains intact under typical solid-phase reaction conditions, and enables a mild photolytic release of 4-subs...

  9. Phase Evolution and Mechanical Behavior of the Semi-Solid SIMA Processed 7075 Aluminum Alloy

    Behzad Binesh


    Full Text Available Microstructural and mechanical behaviors of semi-solid 7075 aluminum alloy were investigated during semi-solid processing. The strain induced melt activation (SIMA process consisted of applying uniaxial compression strain at ambient temperature and subsequent semi-solid treatment at 600–620 °C for 5–35 min. Microstructures were characterized by scanning electron microscope (SEM, energy dispersive spectroscopy (EDS, and X-ray diffraction (XRD. During the isothermal heating, intermetallic precipitates were gradually dissolved through the phase transformations of α-Al + η (MgZn2 → liquid phase (L and then α-Al + Al2CuMg (S + Mg2Si → liquid phase (L. However, Fe-rich precipitates appeared mainly as square particles at the grain boundaries at low heating temperatures. Cu and Si were enriched at the grain boundaries during the isothermal treatment while a significant depletion of Mg was also observed at the grain boundaries. The mechanical behavior of different SIMA processed samples in the semi-solid state were investigated by means of hot compression tests. The results indicated that the SIMA processed sample with near equiaxed microstructure exhibits the highest flow resistance during thixoforming which significantly decreases in the case of samples with globular microstructures. This was justified based on the governing deformation mechanisms for different thixoformed microstructures.

  10. Phase behaviour and gravity-directed self assembly of hard convex spherical caps.

    McBride, John M; Avendaño, Carlos


    We investigate the phase behaviour and self-assembly of convex spherical caps using Monte Carlo simulations. This model is used to represent the main features observed in experimental colloidal particles with mushroom-cap shape [Riley et al., Langmuir, 2010, 26, 1648]. The geometry of this non-centrosymmetric convex model is fully characterized by the aspect ratio χ* defined as the spherical cap height to diameter ratio. We use NPT Monte Carlo simulations combined with free energy calculations to determine the most stable crystal structures and the phase behaviour of convex spherical caps with different aspect ratios. We find a variety of crystal structures at each aspect ratio, including plastic and dimer-based crystals; small differences in chemical potential between the structures with similar morphology suggest that convex spherical caps have the tendency to form polycrystalline phases rather than crystallising into a single uniform structure. With the exception of plastic crystals observed at large aspect ratios (χ* > 0.75), crystallisation kinetics seem to be too slow, hindering the spontaneous formation of ordered structures. As an alternative, we also present a study of directing the self-assembly of convex spherical caps via sedimentation onto solid substrates. This study contributes to show how small changes to particle shape can significantly alter the self-assembly of crystal structures, and how a simple gravity field and a template can substantially enhance the process.

  11. Exploring solid-phase approaches for the preparation of new beta-lactams from amino acids.

    Gerona-Navarro, Guillermo; Royo, Miriam; García-López, Ma Teresa; Albericio, Fernando; González-Muñiz, Rosario


    Two solid-phase approaches, involving the base-assisted intramolecular alkylation of N-chloroacetyl-Phe derivatives anchored to appropriate solid supports, were investigated for the preparation of novel beta-lactams. When a BAL-type strategy was used, the resin-bound azetidinones were easily formed, as established by MAS-NMR, but final compounds could not be removed from the resin, unless a suitable two linkers system was used. In the second approach, in which the Phe residue is anchored to a Wang-type resin through the carboxylate group, the corresponding 1,4,4-trisubstituted 2-azetidinone was obtained in moderate to good yield and high purity.

  12. Anisotropy of the solid-liquid interface properties of the Ni-Zr B33 phase from molecular dynamics simulation

    Wilson, S. R.; Mendelev, M. I.


    Solid-liquid interface (SLI) properties of the Ni-Zr B33 phase were determined from molecular dynamics simulations. In order to perform these measurements, a new semi-empirical potential for Ni-Zr alloy was developed that well reproduces the material properties required to model SLIs in the Ni50.0Zr50.0 alloy. In particular, the developed potential is shown to provide that the solid phase emerging from the liquid Ni50.0Zr50.0 alloy is B33 (apart from a small fraction of point defects), in agreement with the experimental phase diagram. The SLI properties obtained using the developed potential exhibit an extraordinary degree of anisotropy. It is observed that anisotropies in both the interfacial free energy and mobility are an order of magnitude larger than those measured to date in any other metallic compound. Moreover, the [0 1 0] interface is shown to play a significant role in the observed anisotropy. Our data suggest that the [0 1 0] interface simultaneously corresponds to the lowest mobility, the lowest free energy and the highest stiffness of all inclinations in B33 Ni-Zr. This finding can be understood by taking into account a rather complicated crystal structure in this crystallographic direction.

  13. Pattern and phase selection of peritectic reaction during directional solidification

    HUANG; Weidong; (黄卫东); LIN; Xin; (林鑫); WANG; Meng; (王猛); SHEN; Shujuan; (沈淑娟); SU; Yunpeng; (苏云鹏); LIU; Zhenxia; (刘振侠)


    Based on the growth competition between different pattern and phases, the pattern and phase selection during peritectic solidification is analysed by applying the maximum interface temperature criterion to the interface response functions calculated from a numerical model for single phase solidification. The theoretical results agree very well with the experimental results published in literature.

  14. New device for direct extraction of volatiles in solid samples using SPME.

    Ruiz, J; Ventanas, J; Cava, R


    A new device that allows extraction of volatiles from solid materials by SPME, avoiding preparation of the sample, was designed and tested in two different food products. Volatiles from dry-cured ham and canned liver sausage were analyzed by headspace SPME (HS SPME) and by using a new device that protects the SPME fiber in the core of the solid material. Volatile profiles generated by using both methods of extraction were very similar in both products. Compounds that have been previously highlighted as quality markers, such as products from oxidative degradation of lipids, products from Strecker degradation of amino acids, or terpenes, were satisfactorily extracted by SPME coupled to the device for direct extraction. In addition, by using this method no laboratory contaminants were extracted, whereas some major laboratory solvents were presented in the chromatogram using the HS SPME method. However, coefficients of variation were higher when performing the direct sampling procedure. This new device appears to have potential as a simple method for extracting volatiles in solid materials while at the same time avoiding taking samples.

  15. Solid waste management in Croatia in response to the European Landfill Directive.

    Stanic-Maruna, Ira; Fellner, Johann


    The European Landfill Directive 99/31/EC represents the most influential piece of waste legislation on the management of municipal solid waste. In addition to technical standards regarding the design and location of landfills, it calls for a decrease in the amount of biodegradable waste landfilled. In order to meet the reduction targets set in the Landfill Directive, national solid waste strategies need to be changed. This article outlines the impact of the Landfill Directive on the Croatian waste management strategy and discusses the key challenges of its implementation. In addition, three scenarios of future waste management (mechanical biological pre-treatment, waste-to-energy and landfilling) have been investigated and evaluated regarding environmental impacts and affordability. The results of the analysis show that Croatia has transposed the said Directive into its own legislation in an exemplary way. The developed national waste management strategy foresees the set up of a separate collection of recyclables, waste pre-treatment of MSW, as well as the upgrading of existing disposal sites to sanitary landfills. However, the practical progress of carrying out provisions implemented on paper is lagging behind. Concerning the investigated scenarios the results of the evaluation indicate that mechanical biological pre-treatment in conjunction with separate collection of recyclables appears to be the most feasible option (in terms of economic and ecologic parameters). This result is in line with the proposed national waste management strategy.

  16. Multidimensional gas chromatography-mass spectrometry determination of 3-alkyl-2-methoxypyrazines in wine and must. A comparison of solid-phase extraction and headspace solid-phase extraction methods.

    Culleré, Laura; Escudero, Ana; Campo, Eva; Cacho, Juan; Ferreira, Vicente


    Two different strategies for the quantitative determination of 3-alkyl-2-methoxypyrazines in wine and must have been developed and validated. Comparison between both the techniques has been presented and the most adequate has been applied to the determination of these compounds in different samples of wine, made from several varieties of grapes, and also in different samples of must made from Cabernet Sauvignon grapes. Both the methods consisted of a dynamic headspace coupled with a solid-phase extraction (HS-SPE) and solid-phase extraction (SPE) directly from the sample, coupled with multidimensional gas chromatography-mass spectrometry system (MDGC-MS). Both of them require resins LiChrolut EN, and analyte elution has been carried out with dichloromethane. The repeatability of both methodologies was evaluated at two concentration levels. The relative standard deviations (RSD%) were acceptable in every case, but smaller when working with HS-SPE. The recoveries obtained for the three analytes with the two methodologies were almost 100%, with the exception of IBMP, which had a recovery of only 70% with HS-SPE. The linearity was satisfactory with both methods for the range of occurrence of methoxypyrazines in wine and must. The limits of detection of the direct SPE technique were much lower than those of HS-SPE in every case. Direct SPE method detection limits ranged from 0.09 to 0.15 ng L(-1). The method based on direct SPE was chosen finally because it had better detection limits and was easier and quicker than the HS-SPE-based method. It has been applied to the determination of these components in 36 wine and 17 musts samples. The quantitative results suggest that the Spanish wines show meaningless amounts of these compounds. IBMP has been found just in between 1.9 and 15 ng L(-1).

  17. Stereochemistry Control in Direct 1α-Hydroxylation of 5,6-trans-Vitamin D3 by Solid Support

    Yong Bin HAN; Jin Ping CHEN; Bai Ning LIU; Guo Qiang YANG; Yi LI


    A solid-phase synthesis of 1α-hydroxylation of 5,6-trans-vitamin D3 8 is described.The solid phase resin acts as a special protecting group, which gives a higher stereoselectivity in oxidation step than classical protecting groups. The stereochemistry control is favored by using high crosslinkage polymer support in a poor solvent. This work may be of benefit to the synthesis of vitamin D system.

  18. Rheology of sludge from double phase anaerobic digestion of organic fraction of municipal solid waste.

    Battistoni, P; Pavan, P; Mata-Alvarez, J; Prisciandaro, M; Cecchi, F


    In this paper experimental results on the anaerobic digestion of sewage sludge and organic fraction of municipal solid waste (OFMSW) by using a double phase process are reported. The long-term experiment has been carried out on a pilot scale plant, performed in different sets of operative conditions, during which granulometric distributions of particles in sludges and rheological properties of sludges were monitored. A significant fluidification of sludge was evidenced in the meso-thermo process, especially taking into account the variation in sludge behaviour from the first to the second phase. In the thermo-thermo process a fluidification higher than that shown in meso-thermo conditions is not observed, this suggesting that better results in terms of sludge conditioning can be obtained in a long time spent in thermophilic anaerobic digestion. Total volatile solids (TVS) and total fixed solids (TFS) become the most important parameters when mathematical modelling is applied to these processes. In the acidogenic phase, hydraulic retention time (HRT) and temperature are used to determine rigidity coefficient (RC), while only temperature is needed for yield stress (YC). Organic loading rate (OLR) and specific gas production (SGP) exert an important role in methanogenic phase description.

  19. The isolation of soyasaponins by fractional precipitation, solid phase extraction, and low pressure liquid chromatography.

    Gurfinkel, D M; Reynolds, W F; Rao, A V


    Bioactive soyasaponins are present in soybean (Glycine max). In this study, the isolation of soyasaponins in relatively pure form (>80%) using precipitation, solid phase extraction and reverse phase low pressure liquid chromatography (RP-LPLC) is described. Soy flour soyasaponins were separated from non-saponins by methanol extraction and precipitation with ammonium sulphate. Acetylated group A soyasaponins were isolated first by solid phase extraction followed by RP-LPLC (solvent: ethanol-water). Soyasaponins, from a commercial preparation, were saponified and fractionated into deacetylated group A and group B soyasaponins by solid phase extraction (methanol-water). Partial hydrolysis of group B soyasaponins produced a mixture of soyasaponin III and soyasapogenol B monoglucuronide. RP-LPLC of deacetylated group A soyasaponins separated soyasaponin A1 and A2 (38% methanol); of group B soyasaponins isolated soyasaponin I (50% ethanol); and of the partial hydrolysate separated soyasaponin III from soyasapogenol B monoglucuronide (50% ethanol). This methodology provides soyasaponin fractions that are suitable for biological evaluation.

  20. Formation of organic solid phases in hydrocarbon reservoir fluids. Final report

    Andersen, S.I.; Lindeloff, N.; Stenby, E.H.


    The occurrence of solid phases during oil recovery is a potential problem. The present work has mainly been concerned with wax formation due to cooling of oils with a large paraffin content. 8 oils have been included in this project, although only a few of these have till now been subject to all the experimental techniques applied. The oils and wax fractions from these have been characterized using techniques such as GC-MS and Ftir. The goal has in part been to get a detailed description of the oil composition for use in model evaluation and development and in part to get a fundamental understanding of waxy oil properties and behaviour. A high pressure (200 bar) equipment has been developed for automatic detection of wax appearance using a filtration technique and laser light turbidimetry. The latter was found to be far superior to the filtration. The filtration was used to sample the incipient solid phase for characterization. However entrapment of liquid in the filters currently used have hampered this part. A number of model systems and one gas condensate have been investigated. The GC-MS procedure was found only to been able to detect molecules up to n-C45 and the group type analysis was not accurate enough for modelling purposes. Using Ftir it was obvious that incipient phases may contain very complex molecules (asphaltenes) which are not captured by GC-MS especially when fractionation is done using the acetone precipitation at elevated temperature. The latter fractionation procedure has been investigated thoroughly as a tool for understanding wax distribution etc. Within thermodynamic modelling a delta lattice parameter model has been developed which incorporates the non-ideality of the solid phases into the calculation of SLE. The non-ideality is estimated from pure component properties. A new algorithm for phase equilibria involving gas-liquid-solid has been developed. Currently both the model work and the experimental works are continued. (au)

  1. Numerical simulation of predicting and reducing solid particle erosion of solid-liquid two-phase flow in a choke

    Li Guomei; Wang Yueshe; He Renyang; Cao Xuewen; Lin Changzhi; Meng Tao


    Chokes are one of the most important components of downhole flow-control equipment. The particle erosion mathematical model, which considers particle-particle interaction, was established and used to simulate solid particle movement as well as particle erosion characteristics of the solid-liquid two-phase flow in a choke. The corresponding erosion reduction approach by setting ribs on the inner wall of the choke was advanced. This mathematical model includes three parts: the flow field simulation of the continuous carrier fluid by an Eulerian approach, the particle interaction simulation using the discrete particle hard sphere model by a Lagrangian approach and calculation of erosion rate using semi-empirical correlations. The results show that particles accumulated in a narrow region from inlet to outlet of the choke and the dominating factor affecting particle motion is the fluid drag force. As a result, the optimization of rib geometrical parameters indicates that good anti-erosion performance can be achieved by four ribs, each of them with a height (H) of 3 mm and a width (B) of 5 mm equaling the interval between ribs (L).

  2. Determination of multi-class herbicides in soil by liquid-solid extraction coupled with headspace solid phase microextraction method

    Đurović-Pejčev Rada


    Full Text Available A method is described for simultaneous determination of five herbicides (metribuzin, acetochlor, clomazone, oxyfluorfen and dimethenamid belonging to different pesticides groups in soil samples. Developed headspace solid phase microextraction method (HS-SPME in combination with liquid-solid sample preparation (LS was optimized and applied in the analysis of some agricultural samples. Optimization of microextraction conditions, such as temperature, extraction time and sodium chloride (NaCl content was perfor-med using 100 μm polydimethyl-siloxane (PDMS fiber. The extraction effi-ciencies of methanol, methanol:acetone=1:1 and methanol:acetone:hexane= =2:2:1 and the optimum number of extraction steps during the sample prepa-ration, were tested, as well. Gas chromatography-mass spectrometry (GC-MS was used for detection and quantification, obtaining relative standard deviation (RSD below 13%, and recovery values higher than 83% for multiple analyses of soil samples fortified at 30 μg kg-1 of each herbicide. Limits of detection (LOD were less than 1.2 μg kg-1 for all the studied herbicides. [Projekat Ministarstva nauke Republike Srbije, br. TR31043 i br. III43005

  3. Deformability of adsorbents during adsorption and principles of the thermodynamics of solid-phase systems

    Tovbin, Yu. K.


    A microscopic theory of adsorption, based on a discrete continuum lattice gas model for noninert (including deformable) adsorbents that change their lattice parameters during adsorption, is presented. Cases of the complete and partial equilibrium states of the adsorbent are considered. In the former, the adsorbent consists of coexisting solid and vapor phases of adsorbent components, and the adsorbate is a mobile component of the vapor phase with an arbitrary density (up to that of the liquid adsorbate phase). The adsorptive transitioning to the bound state changes the state of the near-surface region of the adsorbent. In the latter, there are no equilibrium components of the adsorbent between the solid and vapor phases. The adsorbent state is shown to be determined by its prehistory, rather than set by chemical potentials of vapor of its components. Relations between the microscopic theory and thermodynamic interpretations are discussed: (1) adsorption on an open surface, (2) two-dimensional stratification of the adsorbate mobile phase on an open homogeneous surface, (3) small microcrystals in vacuum and the gas phase, and (4) adsorption in porous systems.

  4. Quantitative analysis of methacycline hydrochloride by direct potentiometry using the internal solid contact sensor.

    Sun, Xian Xiang; Aboul-Enein, Hassan Y


    An internal solid contact sensor (ISCS) for the determination of methacycline hydrochloride (MC.Cl), Pt/PPy/PVC(MC-PT), is described, based on the use of conducting poly(pyrrole) (PPy) as solid contact material and MC-phosphotungstate (PT) as the ion exchanger and dibutyl phthalate (DBP) as the plasticizer. A direct potentiometric method for the quantitative analysis of MC.Cl is also described. Under the condition of pH 2.7, the linear concentration range, slope (25 degrees C) and detection limit of the sensor are 6.4 x 1.0(-6) - 3.0 x 1.0(-3) M, 52.4 +/- 0.2 mV/decade and 4.4 x 1.0(-6) M, respectively. The response time is potentiometry. The average recovery and relative standard deviation are 100.1 and 0.7% (n = 4), respectively.

  5. Direct observation of large quantum interference effect in anthraquinone solid-state junctions.

    Rabache, Vincent; Chaste, Julien; Petit, Philippe; Della Rocca, Maria Luisa; Martin, Pascal; Lacroix, Jean-Christophe; McCreery, Richard L; Lafarge, Philippe


    Quantum interference in cross-conjugated molecules embedded in solid-state devices was investigated by direct current-voltage and differential conductance transport measurements of anthraquinone (AQ)-based large area planar junctions. A thin film of AQ was grafted covalently on the junction base electrode by diazonium electroreduction, while the counter electrode was directly evaporated on top of the molecular layer. Our technique provides direct evidence of a large quantum interference effect in multiple CMOS compatible planar junctions. The quantum interference is manifested by a pronounced dip in the differential conductance close to zero voltage bias. The experimental signature is well developed at low temperature (4 K), showing a large amplitude dip with a minimum >2 orders of magnitude lower than the conductance at higher bias and is still clearly evident at room temperature. A temperature analysis of the conductance curves revealed that electron-phonon coupling is the principal decoherence mechanism causing large conductance oscillations at low temperature.

  6. Computational model and simulations of gas-liquid-solid three-phase interactions

    Zhang, Lucy; Wang, Chu


    A computational technique to model three-phase (gas-liquid-solid) interactions is proposed in this study. This numerical algorithm couples a connectivity-free front-tracking method that treats gas-liquid multi-fluid interface to the immersed finite element method that treats fully-coupled fluid-solid interactions. The numerical framework is based on a non-boundary-fitted meshing technique where the background grid is fixed where no mesh-updating or re-meshing is required. An indicator function is used to identify the gas from the liquid, and the fluid (gas or liquid) from the solid. Several 2-D and 3-D validation cases are demonstrated to show the accuracy and the robustness of the method. Funding from NRC and CCNI computational facility at Rensselaer Polytechnic Institute are greatly acknowledged.

  7. Solid-phase microextraction and gas chromatography-mass spectrometry for the determination of polycyclic aromatic hydrocarbons in environmental solid matrices.

    Cam, D; Gagni, S; Lombardi, N; Punin, M O


    A solid-phase microextraction (SPME) and gas chromatography-mass spectrometry method for determining polycyclic aromatic hydrocarbons (PAHs) in environmental solid matrices is developed. Investigated matrices include seaweed (Undaria pinnatifida and Himanthalia elongata), humic substances (isolated from a wetland out-flow and purchased from Aldrich), and soil. Optimal conditions for a good SPME efficiency of 16 hydrocarbon compounds are obtained using a 100- micro m polydimethylsiloxane fiber directly immersed in aqueous carrier medium. The method is remarkable for presenting short extraction times and considerably high sensitivities. The SPME results obtained by using internal calibration give the total analyte concentration based on the identical partitioning behavior of native and spiked pollutants. The detection limits range from 0.001 to 0.1 mg of PAH per kilogram of dry matrix. SPME external calibration provides information regarding freely dissolved analytes. The detection limits range from 0.001 to 0.05 micro g of PAH per liter of carrier medium. The SPME with external calibration procedure can be applied to measure free concentrations of a target compound spiked into a carrier medium and onto a matrix. Based on a comparison of results obtained for the two samples, the partitioning of the target analyte between the matrix and the carrier medium is calculated.

  8. Visualization of Protonation/Deprotonation of Active Pharmaceutical Ingredient in Solid State by Vapor Phase Amine-Selective Alkyne Tagging and Raman Imaging.

    Moriyama, Kei; Yasuhara, Yukiko; Ota, Hiromi


    Here, we report a simple and direct method to visualize the protonation/deprotonation of an amine active pharmaceutical ingredient (API) in the solid state using a solid-vapor reaction with propargyl bromide and Raman imaging for the assessment of the API during the manufacturing process of solid formulations. An alkyne tagging occurred on the free form of solid haloperidol by the vapor phase reaction, and a distinct Raman signal of alkyne was detected. Alkyne signal monitoring by Raman imaging enabled us to visualize the distribution of the free-form haloperidol in a solid formulation. On the other hand, haloperidol hydrochloride did not react with propargyl bromide in the solid-vapor reaction, and the alkyne signal was not observed. Using the difference in reactivity, the protonation/deprotonation of the amine API in the solid state could be visualized. As an example of application, we tried to visually assess the protonation/deprotonation state when the free-form haloperidol was ground with acids using the solid-vapor reaction and Raman imaging and found that haloperidol was partially protonated when ground with 2 equivalents of hydrogen chloride. Furthermore, we demonstrated the relationship between the degree of protonation and the amount of water added as a medium for grinding haloperidol with succinic acid. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  9. Numerical modeling of two-phase high speed jet with non-equilibrium solid phase crystallization

    Molchanov, A. M.; Yanyshev, D. S.; Bykov, L. V.


    The main purpose of the paper is to demonstrate that the Euler approach is fully applicable to the multiphase flows with discrete phase undergoing phase transitions. It is carried out using the example of a jet flow with aluminium oxide particles non-equilibrium crystallization. The jet is strongly underexpanded. The non-equilibrium molecular effects are being taken into account. The obtained results of the simulations are in good agreement with the works of the other authors. The developed Euler approach proved itself to be the most robust in flows with complex flow geometry.

  10. Insights into solid phase characteristics and release of heavy metals and arsenic from industrial sludge via combined chemical, mineralogical, and microanalysis.

    Dung, Tran Thi Thu; Golreihan, Asefeh; Vassilieva, Elvira; Phung, Nguyen Ky; Cappuyns, Valérie; Swennen, Rudy


    This study investigates the solid phase characteristics and release of heavy metals (i.e., Cd, Co, Cu, Cr, Mo, Ni, Pb, and Zn) and arsenic (As) from sludge samples derived from industrial wastewater treatment plants. The emphasis is determining the influence of acidification on element mobilization based on a multidisciplinary approach that combines cascade and pHstat leaching tests with solid phase characterization through X-ray diffraction (XRD), field emission gun electron probe micro analysis (FEG-EPMA), and thermodynamic modeling (Visual MinteQ 3.0). Solid phase characterization and thermodynamic modeling results allow prediction of Ni and Zn leachabilities. FEG-EPMA is useful for direct solid phase characterization because it provides information on additional phases including specific element associations that cannot be detected by XRD analysis. Cascade and pHstat leaching test results indicate that disposal of improperly treated sludges at landfills may lead to extreme environmental risks due to high leachable concentrations of Zn, Ni, Cu, Cr, and Pb. However, high leachabilities under acid conditions of Ni and Zn as observed from pHstat leaching test results may provide a potential opportunity for acid extraction recovery of Ni and Zn from such sludges.

  11. A Facile, Choline Chloride/Urea Catalyzed Solid Phase Synthesis of Coumarins via Knoevenagel Condensation

    Hosanagara N. Harishkumar


    Full Text Available The influence of choline chloride/urea ionic liquid in solid phase on the Knoevenagel condensation is demonstrated. The active methylene compounds such as meldrum’s acid, diethylmalonate, ethyl cyanoacetate, dimethylmalonate, were efficiently condensed with various salicylaldehydes in presence of choline chloride/urea ionic liquid without using any solvents or additional catalyst. The reaction is remarkably facile because of the air and water stability of the catalyst, and needs no special precautions. The reactions were completed within 1hr with excellent yields (95%. The products formed were sufficiently pure, and can be easily recovered. The use of ionic liquid choline chloride/urea in solid phase offered several significant advantages such as low cost, greater selectivity and easy isolation of products.

  12. Silica-Based Solid Phase Extraction of DNA on a Microchip

    陈晓芳; 沈科跃; 刘鹏; 郭旻; 程京; 周玉祥


    Micro total analysis systems for chemical and biological analysis have attracted much attention.However,microchips for sample preparation and especially DNA purification are still underdeveloped.This work describes a solid phase extraction chip for purifying DNA from biological samples based on the adsorption of DNA on bare silica beads prepacked in a microchannel.The chip was fabricated with poly-dimethylsiloxane.The silica beads were packed in the channel on the chip with a tapered microchannel to form the packed bed.Fluorescence detection was used to evaluate the DNA adsorbing efficiency of the solid phase.The polymerase chain reaction was used to evaluate the quality of the purified DNA for further use.The extraction efficiency for the DNA extraction chip is approximately 50% with a 150-nL extraction volume.Successful amplification of DNA extracted from human whole blood indicates that this method is compatible with the polymerase chain reaction.

  13. Solid phase epitaxy amorphous silicon re-growth: some insight from empirical molecular dynamics simulation

    Krzeminski, Christophe; 10.1140/epjb/e2011-10958-7


    The modelling of interface migration and the associated diffusion mechanisms at the nanoscale level is a challenging issue. For many technological applications ranging from nanoelectronic devices to solar cells, more knowledge of the mechanisms governing the migration of the silicon amorphous/crystalline interface and dopant diffusion during solid phase epitaxy is needed. In this work, silicon recrystallisation in the framework of solid phase epitaxy and the influence on orientation effects have been investigated at the atomic level using empirical molecular dynamics simulations. The morphology and the migration process of the interface has been observed to be highly dependent on the original inter-facial atomic structure. The [100] interface migration is a quasi-planar ideal process whereas the cases [110] and [111] are much more complex with a more diffuse interface. For [110], the interface migration corresponds to the formation and dissolution of nanofacets whereas for [111] a defective based bilayer reor...

  14. Experimental setup for investigating silicon solid phase crystallization at high temperatures.

    Schmidt, Thomas; Gawlik, Annett; Schneidewind, Henrik; Ihring, Andreas; Andrä, Gudrun; Falk, Fritz


    An experimental setup is presented to measure and interpret the solid phase crystallization of amorphous silicon thin films on glass at very high temperatures of about 800 °C. Molybdenum-SiO(2)-silicon film stacks were irradiated by a diode laser with a well-shaped top hat profile. From the relevant thermal and optical parameters of the system the temperature evolution can be calculated accurately. A time evolution of the laser power was applied which leads to a temperature constant in time in the center of the sample. Such a process will allow the observation and interpretation of solid phase crystallization in terms of nucleation and growth in further work.

  15. The Use of Aryl Hydrazide Linkers for the Solid Phase Synthesis of Chemically Modified Peptides

    Woo, Y; Mitchell, A R; Camarero, J A


    Since Merrifield introduced the concept of solid phase synthesis in 1963 for the rapid preparation of peptides, a large variety of different supports and resin-linkers have been developed that improve the efficiency of peptide assembly and expand the myriad of synthetically feasible peptides. The aryl hydrazide is one of the most useful resin-linkers for the synthesis of chemically modified peptides. This linker is completely stable during Boc- and Fmoc-based solid phase synthesis and yet it can be cleaved under very mild oxidative conditions. The present article reviews the use of this valuable linker for the rapid and efficient synthesis of C-terminal modified peptides, head-to-tail cyclic peptides and lipidated peptides.

  16. 西仑吉肽的固相合成%Solid phase synthesis of cilengitide

    张波; 王卫国; 康武; 智小霞; 姚忠; 徐红岩


    Fully-protected linear peptide was synthesized by Fmoc solid phase peptide synthesis methods. The solid phase carrier was 2-chlorotrityl chloride resin. HATU/HOBt and HBTU/HOBt were used as the coupling reagents. The synthesis of fully-protected cyclic peptide used THF/DCM ( at a ratio of 1: 1 by volume) as the solvent and HATU/HOBt as the coupling reagents. Finally cilengitide could be obtained by deprotection reaction.%采用Fmoc固相合成法,选用2-氯三苯甲基氯树脂作为固相载,HBTU/HOBt和HATU/HOBt为缩合剂,合成全保护线性肽.以V(DCM)∶V(THF)= 1∶1为溶剂,HATU/HOBt为缩合剂,合成全保护环肽.最后脱除保护基得终产物西仑吉肽.

  17. Dense Pellicular Agarose-Glass Beads for Expanded Bed Application: Flow Hydrodynamics and Solid Phase Classifications

    周鑫; 史清洪; 白姝; 孙彦


    Two dense pellicular agarose-glass matrices of different sizes and densities, i.e., AG-S and AG-L, have been characterized for their bed expansion behavior, flow hydrodynamics and particle classifications in an expanded bed system. A 26 mm ID column with side ports was used for sampling the liquid-solid suspension during expanded bed operations. Measurements of the collected solid phase at different column positions yielded the particle size and density distribution data. It was found that the composite matrices showed particle size as well as density classifications along the column axis, i.e., both the size and density of each matrix decreased with increasing the axial bed height. Their axial classifications were expressed by a correlation related to both the particle size and density as a function of the dimensionless axial bed height. The correlation was found to fairly describe the solid phase classifications in the expanded bed system. Moreover, it can also be applied to other two commercial solid matrices designed for expanded bed applications.

  18. Investigation of phase diagrams and physical stability of drug-polymer solid dispersions.

    Lu, Jiannan; Shah, Sejal; Jo, Seongbong; Majumdar, Soumyajit; Gryczke, Andreas; Kolter, Karl; Langley, Nigel; Repka, Michael A


    Solid dispersion technology has been widely explored to improve the solubility and bioavailability of poorly water-soluble compounds. One of the critical drawbacks associated with this technology is the lack of physical stability, i.e. the solid dispersion would undergo recrystallization or phase separation thus limiting a product's shelf life. In the current study, the melting point depression method was utilized to construct a complete phase diagram for felodipine (FEL)-Soluplus® (SOL) and ketoconazole (KTZ)-Soluplus® (SOL) binary systems, respectively, based on the Flory-Huggins theory. The miscibility or solubility of the two compounds in SOL was also determined. The Flory-Huggins interaction parameter χ values of both systems were calculated as positive at room temperature (25 °C), indicating either compound was miscible with SOL. In addition, the glass transition temperatures of both solid dispersion systems were theoretically predicted using three empirical equations and compared with the practical values. Furthermore, the FEL-SOL solid dispersions were subjected to accelerated stability studies for up to 3 months.

  19. Molecular simulation of homogeneous crystal nucleation of AB2 solid phase from a binary hard sphere mixture

    Bommineni, Praveen Kumar; Punnathanam, Sudeep N.


    Co-crystal formation from fluid-mixtures is quite common in a large number of systems. The simplest systems that show co-crystal (also called substitutionally ordered solids) formation are binary hard sphere mixtures. In this work, we study the nucleation of AB2 type solid compounds using Monte Carlo molecular simulations in binary hard sphere mixtures with the size ratio of 0.55. The conditions chosen for the study lie in the region where nucleation of an AB2 type solid competes with that of a pure A solid with a face-centered-cubic structure. The fluid phase composition is kept equal to that of the AB2 type solid. The nucleation free-energy barriers are computed using the seeding technique of Sanz et al. [J. Am. Chem. Soc. 135, 15008 (2013)]. Our simulation results show that the nucleation of the AB2 type solid is favored even under conditions where the pure A solid is more stable. This is primarily due to the similarity in the composition of the fluid phase and the AB2 type solid which in turn leads to much lower interfacial tension between the crystal nucleus and the fluid phase. This system is an example of how the fluid phase composition affects the structure of the nucleating solid phase during crystallization and has relevance to crystal polymorphism during crystallization processes.

  20. Thermodynamic Model Formulations for Inhomogeneous Solids with Application to Non-isothermal Phase Field Modelling

    Gladkov, Svyatoslav; Kochmann, Julian; Reese, Stefanie; Hütter, Markus; Svendsen, Bob


    The purpose of the current work is the comparison of thermodynamic model formulations for chemically and structurally inhomogeneous solids at finite deformation based on "standard" non-equilibrium thermodynamics [SNET: e. g. S. de Groot and P. Mazur, Non-equilibrium Thermodynamics, North Holland, 1962] and the general equation for non-equilibrium reversible-irreversible coupling (GENERIC) [H. C. Öttinger, Beyond Equilibrium Thermodynamics, Wiley Interscience, 2005]. In the process, non-isothermal generalizations of standard isothermal conservative [e. g. J. W. Cahn and J. E. Hilliard, Free energy of a non-uniform system. I. Interfacial energy. J. Chem. Phys. 28 (1958), 258-267] and non-conservative [e. g. S. M. Allen and J. W. Cahn, A macroscopic theory for antiphase boundary motion and its application to antiphase domain coarsening. Acta Metall. 27 (1979), 1085-1095; A. G. Khachaturyan, Theory of Structural Transformations in Solids, Wiley, New York, 1983] diffuse interface or "phase-field" models [e. g. P. C. Hohenberg and B. I. Halperin, Theory of dynamic critical phenomena, Rev. Modern Phys. 49 (1977), 435-479; N. Provatas and K. Elder, Phase Field Methods in Material Science and Engineering, Wiley-VCH, 2010.] for solids are obtained. The current treatment is consistent with, and includes, previous works [e. g. O. Penrose and P. C. Fife, Thermodynamically consistent models of phase-field type for the kinetics of phase transitions, Phys. D 43 (1990), 44-62; O. Penrose and P. C. Fife, On the relation between the standard phase-field model and a "thermodynamically consistent" phase-field model. Phys. D 69 (1993), 107-113] on non-isothermal systems as a special case. In the context of no-flux boundary conditions, the SNET- and GENERIC-based approaches are shown to be completely consistent with each other and result in equivalent temperature evolution relations.

  1. Investigation on Dynamic Calibration for an Optical-Fiber Solids Concentration Probe in Gas-Solid Two-Phase Flows

    Changsui Zhao; Liu Shen; Pan Xu; Xiaoping Chen; Daoyin Liu; Cai Liang; Guiling Xu


    This paper presents a review and analysis of the research that has been carried out on dynamic calibration for optical-fiber solids concentration probes. An introduction to the optical-fiber solids concentration probe was given. Different calibration methods of optical-fiber solids concentration probes reported in the literature were reviewed. In addition, a reflection-type optical-fiber solids concentration probe was uniquely calibrated at nearly full range of the solids concentration from 0...


    张政; 谢灼利


    Numerical simulation of fluid-solid two-phase flows is reviewed with 105 references. There are two approaches (Lagrangian approach and Eulerian approach) typically used for modeling fluid-solid flows. The former treats the fluid phase as continuous phase and the solid phase as dispersed phase and predicts the particle trajectories in the fluid phase as the results of forces acting on particles.The latter treats the solid as a certain kind of continuum and solves two continuum equations for both fluid and solid phase.   At first, as the basis of fluid-solid two-phase flow, several turbulence models, such as Reynolds Association Numerical Simulation (RANS), Direct Numerical Simulation (DNS), Large Eddy Simulation (LES) and Discrete Vortex Simulation (DVS), for the continuous fluid phase are summarized,and the mechanisms of RANS are discussed in detail.   In the Lagrangian approach, a particle kinetic equation is presented and the importance of each force acting on a particle is discussed. For a flow with dense particles, various interaction models between particles are discussed, among which the Distinct Element Method (DEM) newly developed from rock deformation study is particularly described, and the new method shows great predicting ability.   In the Eulerian approach, the basis equations for the solid and fluid phases as well as their numerical treatments are presented. To close the turbulence and phase related equations, calculation of solid phase viscosity and pressure are discussed respectively. Finally, a k-ε-kp model and model derived from kinetic theory of granular flow are especially introduced.   As a complement, a discussion of one-way coupling and two-way coupling between fluid and solid phase is included.   Based on the review of the advantages and disadvantages of all models, the existing problems and the future development direction of fluid-solid two phase flow are given as conclusions.%鉴于流体-固体两相流及其数

  3. Design of indirect solid-phase immunosorbent methods for detecting arenavirus antigens and antibodies

    Ivanov, A.P.; Rezapkin, G.V.; Dzagurova, T.K.; Tkachenko, E.A.


    Specifications have been elaborated for formulating indirect solid-phase enzyme-linked immunosorbent assay (ELISA) and radioimmunoassay (SPRIA) methods that employ anti-human and anti-mice G class immunoglobulin (IgG), conjugated with horseradish peroxidase and /sup 125/I for detecting the arenaviruses Junin, Machupo, Tacaribe, Amalpari, Tamiami, Lassa, and LCM (lymphocytic choriomeningitis). These methods make it possible to identify with a high degree of sensitivity arenavirus antigens and antibodies in various kinds of material.

  4. Phase I Study of Continuous Weekly Dosing of Dimethylamino Benzoylphenylurea (BPU) in Patients with Solid Tumours

    Messersmith, Wells A.; Rudek, Michelle A.; Baker, Sharyn D.; Zhao, Ming; Collins, Connie; Colevas, A. Dimitrios; Donehower, Ross C.; Carducci, Michael A.; Wolff, Antonio C.


    A phase I study of Dimethylamino Benzoylphenylurea (BPU), a tubulin inhibitor, was performed using a weekly continuous schedule. Patients with refractory solid tumours received oral BPU once weekly without interruption at doses ranging from 5 to 320mg using an accelerated titration design. Nineteen subjects received 54 cycles of BPU. Early pharmacokinetic findings of decreased clearance with increasing dose and plasma accumulation led to the expansion of the 320mg dose level. Two subjects the...

  5. Zirconyl chloride promoted highly efficient solid phase synthesis of amide derivatives


    An efficient solid phase route for the synthesis of amide derivatives by the reaction of carboxylic acids with urea in the presence of catalytic amount of zirconyl chloride under microwave irradiation conditions was described. In this way, a range of interesting amide derivatives was obtained in good to excellent yields. The catalyst was recycled with fresh reactants and it gave almost similar results without significant loss of activity up to the third run.

  6. R. Bruce Merrifield and Solid-Phase Peptide Synthesis: A Historical Assessment

    Mitchell, A R


    Bruce Merrifield, trained as a biochemist, had to address three major challenges related to the development and acceptance of solid-phase peptide synthesis (SPPS). The challenges were (1) to reduce the concept of peptide synthesis on a insoluble support to practice, (2) overcome the resistance of synthetic chemists to this novel approach, and (3) establish that a biochemist had the scientific credentials to effect the proposed revolutionary change in chemical synthesis. How these challenges were met is discussed in this article.

  7. Numerical study of light-induced phase behavior of smectic solids

    Chung, Hayoung; Park, Jaesung; Cho, Maenghyo


    By the chemical cross-linking of rigid molecules, liquid crystal polymer (LCP) has been envisaged as a novel heterogeneous material due to the fact that various optical and geometric states of the liquid crystalline (LC) phases are projected onto the polymeric constituents. The phase behavior, which refers to the macroscopic shape change of LCP under thermotropic phase change, is a compelling example of such optical-mechanical coupling. In this study, the photomechanical behavior, which broadly refers to the thermal- or light-induced actuation of smectic solids, is investigated using three-dimensional nonlinear finite element analysis (FEA). First, the various phases of LC are considered as well as their relation to polymeric conformation defined by the strain energy of the smectic polymer; a comprehensive constitutive equation that bridges the strong, optomechanical coupling is then derived. Such photomechanical coupling is incorporated in the FEA considering geometric nonlinearity, which is vital to understanding the large-scale light-induced bending behavior of the smectic solid.To demonstrate the simulation capability of the present model, numerous examples of photomechanical deformations are investigated parametrically, either by changing the operating conditions such as stimuli (postsynthesis) or the intrinsic properties (presynthesis). When compared to nematic solids, distinguished behaviors due to smectic substances are found herein and discussed through experiments. The quasisoftness that bidirectionally couples microscopic variables to mechanical behavior is also explained, while considering the effect of nonlinearity. In addition to providing a comprehensive measure that could deepen the knowledge of photomechanical coupling, the use of the proposed finite element framework offers an insight into the design of light-responsive actuating systems made of smectic solids.

  8. A New Molecularly Imprinted Polymer for Solid-phase Extraction of Cotinine from Human Urine

    Jun YANG; Xiao Lan ZHU; Ji Bao CAI; Qing De SU; Yun GAO; Liang ZHANG


    A molecularly imprinted polymer (MIP), prepared around a cotinine template, has been synthesized. The feasibility of using the polymer for solid-phase extraction (SPE) of cotinine from biological samples has been investigated. The results show that cotinine can be quantitatively retained and eluted from the polymer. Experiments with human urine samples indicate that clean target analyte is obtained for HPLC with UV detection using the protocol.

  9. Kinetics of solid state phase transformations: Measurement and modelling of some basic issues

    S Raju; E Mohandas


    A brief review of the issues involved in modelling of the solid state transformation kinetics is presented. The fact that apart from the standard thermodynamic parameters, certain path variables like heating or cooling rate can also exert a crucial influence on the kinetic outcome is stressed. The kinetic specialties that are intrinsic to phase changes proceeding under varying thermal history are enumerated. A simple and general modelling methodology for understanding the kinetics of non-isothermal transformations is outlined.

  10. Selective fiber used for headspace solid-phase microextraction of abused drugs in human urine

    Sunanta Wangkarn


    A sensitive and selective fiber for simultaneous analysis of three drugs of abuse (amphetamine, methamphetamine and ephedrine) in urine samples was explored using headspace solid phase microextraction and gas chromatography with flame ionization detection. Several parameters affecting extraction such as extraction time, extraction temperature, pH of solution and salt concentrations were investigated. Among five commercially available fibers, divinylbenzene/carboxen/ polydimethylsiloxane is th...

  11. Fmoc solid-phase synthesis of peptide thioesters by masking as trithioortho esters

    Brask, Jesper; Albericio, F.; Jensen, Knud Jørgen


    Total chemical synthesis of proteins by chemoselective ligation relies on C-terminal peptide thioesters as building blocks. Their preparation by standard Fmoc solid-phase peptide synthesis is made difficult by the lability of thioesters to aminolysis by the secondary amines used for removal of th...... of the Fmoc group. Here we present a novel backbone amide linker (BAL) strategy for their synthesis in which the thioester functionality is masked as a trithioortho ester throughout the synthesis....

  12. Solid-phase microextraction for flavor analysis in Harari Khat (Catha edulis) stimulant

    AL-FLAHI Abdulsalam; ZOU Jian-kai (邹建凯); YIN Xue-feng (殷学锋)


    This research examined the typical flavor compounds in the commonest type of Khat called Harari Khat grown in the region of Ethiopia. Twenty-eight compounds, which includes 1,2-Propanedione, 1-Phenyl, Hexanol, Hexanal compounds, Limonene, Benzaldehyde with other flavors, were extracted by polydimethylsiloxane at room temperature for 30 min from Khat samples, and identified by solid-phase microextraction-gas chromatography-mass spectrometry (SPME- GC-MS). This method needs no organic solvents and required minimal sample.

  13. Effect of Microwave Radiation on Enzymatic and Chemical Peptide Bond Synthesis on Solid Phase

    Alessandra Basso


    Full Text Available Peptide bond synthesis was performed on PEGA beads under microwave radiations. Classical chemical coupling as well as thermolysin catalyzed synthesis was studied, and the effect of microwave radiations on reaction kinetics, beads' integrity, and enzyme activity was assessed. Results demonstrate that microwave radiations can be profitably exploited to improve reaction kinetics in solid phase peptide synthesis when both chemical and biocatalytic strategies are used.

  14. Two phase continuous digestion of solid manure on-farm: design, mass and nutrient balance

    Schäfer, Winfried; Evers, Lars; Lehto, Marja; Sorvala, Sanna; Teye, Frederick; Granstedt, Artur


    During the last decade some so called ‘dry fermentation’ prototype plants were developed for anaerobic digestion of organic material containing 15-50 % total solids. These plants show added advantages com-pared to slurry digestion plants: Less reactor volume, less process energy, less transport capacity, less odour emissions. However on-farm dry fermentation plants are not common and rarely commercially available. This paper reports about an innovative two phase prototype biogas plant designe...

  15. Solid-Phase Organic Synthesis of Aryl Vinyl Ethers Using Sulfone-Linking Strategy

    余腊妹; 汤妮; 盛寿日; 陈茹冰; 刘晓玲; 蔡明中


    A novel facile solid-phase organic synthesis of aryl vinyl ethers by reaction of polystyrene-supported 2-phenylsulfonylethanol with phenols under Mitsunobu conditions and subsequent elimination reaction with DBU has been developed. The advantages of this method include straightforward operation, good yield and high purity of the products. Alternatively, a typical example of Suzuki coupling reaction on-resin was further applied to prepare 4-phenylphenyl vinyl ether for extending this method.

  16. Solid-phase reduction of Cr2O3 under chemical catalytic conditions

    Simonov, V. K.; Grishin, A. M.


    The kinetics of the solid-phase reduction of Cr2O3 with carbon under chemical catalytic action on the reacting system is studied. A significant intensification of the process in the presence of small amounts of potassium and sodium salts is established. The concepts of the catalyst action mechanism are considered and experimentally substantiated. Manufacture of iron-chromium master alloys with a restricted content of carbon can be organized at low temperatures, and they can be used in steelmaking.

  17. Preparation of high-quality poly-Si films by a solid phase crystallizing method

    Yao Ruo He


    A solid phase crystallizing method has been developed to grow a Si crystal at temperatures as low as 550 degree C. Using this method, a high-quality thin-film polycrystalline silicon (Poly-Si) was obtained. The largest grain size, examined with X-ray diffraction spectroscopy and scanning electron microscopy images of recrystallized samples, is approximately 1 mu m for substrate temperature at 300 degree C and annealed at 550 degree C for 3 hours

  18. The Synthesis of QADMAA and its Application to the Solid Phase ...

    and the solid phase extraction of the Co(II)-QADMAA chelate with C18 membrane disks was .... For up to 2.4 µg of Co(II), the use of about 5~10 mL 5 × 10–4 ..... 22 benzoic acid. 2-(3,5-Dibromo-2-pyridylazo)-diaminotoluene. pH 4–8. 590. 13.4.

  19. Optimizing the optical field distribution of solid immersion lens system by a continuous phase filter

    Xuehua Ye; Yaoju Zhang; Junfeng Chen


    In solid immersion lens (SIL) microscopy systems with high numerical aperture (NA), there always exists the aberration produced by Fresnel effects at the interface between SIL and the sample. This aberration may cause the degradation of the image of sample. We design a continuous phase filter and optimize the optical field distribution of SIL system. The numerical results show that when the continuous phase filter is used, the field distribution of SIL system can be optimized, and the focal depth and intensity of transmitted light can be increased. At the same time, the intensity of side-lobe and the resolution are kept almost unchanged.

  20. Diffusionless phase transition with two order parameters in spin-crossover solids

    Gudyma, Iurii, E-mail:; Ivashko, Victor [Department of General Physics, Chernivtsi National University, 58012 Chernivtsi (Ukraine); Linares, Jorge [Groupe d' Etude de la Matière Condensée (GEMAC), UMR 8635, CNRS, Université de Versailles Saint Quentin, 45 avenue des Etats-Unis, 78035 Versailles (France)


    The quantitative analysis of the interface boundary motion between high-spin and low-spin phases is presented. The nonlinear effect of the switching front rate on the temperature is shown. A compressible model of spin-crossover solid is studied in the framework of the Ising-like model with two-order parameters under statistical approach, where the effect of elastic strain on interaction integral is considered. These considerations led to examination of the relation between the order parameters during temperature changes. Starting from the phenomenological Hamiltonian, entropy has been derived using the mean field approach. Finally, the phase diagram, which characterizes the system, is numerically analyzed.